Human Bio 156

Unit 4 Self-Evaluation

2008-07-18T12:43:00.002-07:00

1. What were the three aspects of the assignments I've submitted that I am most proud of?
-> The lab project. I really like a few of my pictures that I took.
-> The embryonic and fetal development lab.
-> My compendiums

2. What two aspects of my submitted assignments do I believe could have used some improvement?
-> The only one I have for this unit is I'm not that crazy about my essay.

3. What do I believe my overall grade should be for this unit?
-> A

4. How could I perform better in the next unit?
-> Hip, hip, hooray, this is the last unit! :)

Unit 4 Ethical Essay: World Resource Use

2008-07-18T11:27:00.004-07:00

You and Me

Energy consumption, population growth, conservation, recycling. They are all such complex topics. How do we best help ourselves and our precious land. What do we do now so that we do not leave our descendents with an unfixable situation. It seems many of the solutions that are discovered to help us conserve our resources are later found to be damaging in a way that was at first not considered. Take, for instance, the practice of recycling. I know that I feel good when I recycle. I know that I am reducing the amount of material that will be dumped in the local landfill. But do my actions result in a net benefit for the environment? I do not have recycling pick up at my house. I have to drive to Sun Dog Ranch Road to drop it off. From there, I'm sure some big diesel burning garbage truck delivers all of the recyclables to processing plant. How far does that truck have to travel beforing reaching the processing plant? Do some goods get delivered to one plant and the others to a different plant? How much energy and other valuable resources do the processing plants have to expend to break my recyclables down into a reusable form? I don't know the answers to these questions, but I do wonder, do we end up with a net benefit or not? Again, these are hugely complex topics with no simple solutions.

Recycling is big here in the US and hopefully in all of the other developed countries of the world. Do they have recycling progroms in 3rd world countries? I am sure they do not. They also do not have individually packaged granola bars and disposable toilet bowl brushes. So the problems that we face today must vary by region and country. The US and other industrialized countries have focused on reducing population growth to a sustainable level. 3rd world countries have not. Should they? Absolutely. Although energy consumption per person is so much less in those countries, so is their supply of naturaly resources. In addition, progress towards leveling off the population growth there needs to start now. We all need to do our part.

More importantly, the industrialized countries of the world need to stay focused on reducing energy consumption and finding renewable sources of energy. Subjects like these can at times feel like they are far off in the distance. They can be topics we do not need to worry about today or that we leave for someone else to worry about. I, personally, am probably not going to solve the world's energy crisis. So why do I need to think about it. The reason is simple. We all can do our part. We can all turn our air conditioner up a degree or two and our heater down a few degrees. We can all change out our incandescent light bulbs to compact fluorescents. Some of us can ride our bikes to school or work instead of driving our cars. We can choose paperless billing and e-statements instead of receiving paper copies every month. Ways in which each and every one of us can contribute are out there, we just need to put them into practice.

Unit 4 Lab Project: List of Species

2008-07-13T07:11:00.005-07:00

one
Scientific name: Prunus avium
Common name: Bing cherry
Interaction: Symbiotic. Provide food to humans. Humans provide CO2, farmers nurture and multiply the species.
Domesticated: Yes. Farmers raise cherry trees.
Future: Symbiotic relationship will hopefully continue! I love cherries.

two
Scientific name: Canis familiaris
Common name: Beagle
Interaction: Symbiotic. Humans breed and care for beagles...house them, feed them. Beagles are watchdogs (in terms of altering owners to potential invaders) and great companions.
Domesticated: Yes.
Future: Symbiotic relationship will continue.

three
Scientific name: Acer griseum
Common name: Paperbark maple
Interaction: Symbiotic. Humans provide CO2, plant and nurture. Provide oxygen, shade, beauty, enjoyment to humans.
Domesticated: Yes. Farmers raise these trees to sell for others to plant and nurture.
Future: Symbiotic relationship will continue.

four
Scientific name: Zinnia sp.
Common name: Zinnia
Interaction: Symbiotic. Humans plant and care for. Zinnias provide beauty, enjoyment.
Domesticated: Yes. Farmers raise zinnias to sell.
Future: Symbiotic relationship will continue.

five
Scientific name: Taxodium distichum
Common name: Bald cypress
Interaction: Symbiotic. Humans provide CO2 and care for trees. Bald cypress provides oxygen, shade, beauty, enjoyment
Domesticated: Yes.
Future: Symbiotic relationship will continue.

six
Scientific name: Clupea harengus
Common name: Sardines.
Interaction: Predation. I have tried to think of a way that humans are of some benefit to herring, but I have not been able to come up with any!
Domesticated: No.
Future: Predation will continue. Humans will continue to hunt and eat herring.

seven
Scientific name: Scolopendra heros
Common name: Giant desert centipede
Interaction: Commensal/symbiotic. They benefit humans by eating cockroaches. The thought is revolting to me, but some people may keep them as pets!!!
Domesticated: No.
Future: I think the relationshiop will remain mostly commensal.

eight
Scientific name: Sylvilagus floridanus
Common name: Eastern cottontail
Interaction: Symbiotic. Unfortunately, humans provide tasty vegetation for rabbits. Some humans eat rabbits.
Domesticated: Yes, some species.
Future: Symbiotic relationship will continue.

nine
Scientific name: Casmerodius albus
Common name: Great egret
Interaction: Symbiotic...maybe mutualistic. Humans provide retention ponds as a habitat for the egret. The bird provides beauty and enjoyment.
Domesticated: No.
Future: Symbiotic/mutualistic relationship will continue.

ten
Scientific name: Acer palmatum atropurpureum
Common name: Red Japanese Maple
Interaction: Symbiotic. Provide oxygen, beauty, enjoyment to humans. Humans provide CO2, plant and care for.
Domesticated: Yes. Humans must nurture them.
Future: Symbiotic relationship will continue.

eleven
Scientific name: Fagus sylvatica 'Tricolor'
Common name: Tricolor European Beech
Interaction: Symbiotic. Provides oxygen, beauty, enjoyment to humans. Humans multiply and care for.
Domesticated: Yes. See above.
Future: Symbiotic relationship will continue.

twelve
Scientific name: Lycopersicon esculentum L
Common name: Tomato
Interaction: Symbiotic. Tomatoes provide food, humans raise and care for the plants.
Domesticated: Yes. Farmers raise them.
Future: Symbiotic relationship will continue.

thirteen
Scientific name: Zea mays
Common name: Sweet corn
Interaction: Symbiotic. Sweet corn provides food for humans. Humans plant corn like crazy.
Domesticated: Yes. Farmers raise corn.
Future: Symbiotic relationship will continue.

fourteen
Scientific name: Malus domestica Borkh
Common name: Braeburn apple
Interaction: Symbiotic. Apple tree provides food to humans. Humans plant and nurture the trees.
Domesticated: Yes. Farmers raise apple trees.
Future: Symbiotic relationship will continue.

fifteen
Scientific name: Vaccinium corymbosum
Common name: Blueberry
Interaction: Symbiotic. Bush provides delicious fruit to humans. Humans plant and care for the plant.
Domesticated: Yes. Farmers raise blueberry bushes.
Future: Symbiotic relationship will continue.

sixteen
Scientific name: Asparagus officinalis
Common name: Garden asparagus
Interaction: Symbiotic. Asparagus is food for humans and humans plant it.
Domesticated: Yes.
Future: Symbiotic relationship will continue.

seventeen
Scientific name: Fragaria ananassa
Common name: Strawberry
Interaction: Symbiotic. Strawberry is a tasty food for humans. Humans plant the strawberry bush.
Domesticated: Yes.
Future: Symbiotic relationship will continue.

eighteen
Scientific name: Lactuca sativa
Common name: Leaf lettuce
Interaction: Symbiotic. Lettuce is a food source for humans. Humans plant many seeds a year to grow lettuce.
Domesticated: Yes. Farmers raise lettuce.
Future: Symbiotic relationship will continue.

nineteen
Scientific name: Arachis hypogaea L.
Common name: Peanut
Interaction: Symbiotic.
Domesticated: Yes. Farmers raise peanut plants.
Future: Symbiotic relationship will continue.

twenty
Scientific name: Achillea millefolium
Common name: Yarrow
Interaction: Symbiotic. Yarrow provide beauty and oxygen to humans. Humans plant and nurture yarrow.
Domesticated: Yes. Farmers raise yarrow to sell to others.
Future: Symbiotic relationship will continue.

Unit 4, Online Lab #2: Demographics

2008-07-13T07:06:00.005-07:00

SIMULATION SCREEN SHOTS

World and low fertility rate (Greece):

World and high fertility rate (Zaire):

QUESTIONS AND ANSWERS

1. What was your high fertility rate country and what was its fertility rate?
-> The high fertility rate country that I chose was Zaire. Its fertility rate was 6.10.

2. What was your low fertility rate country and what was its fertility rate?
-> The low fertility rate country that I chose was Greece. Its fertility rate was 1.50.

3. The initial demographic "shape" of your high fertility rate country should have been a pyramid, with high population in young age groups. Explain why high fertility rate results in a high percentage of young people in the population. How does this affect future population growth?
-> A high fertility rate means that on average couples are having more than 2 kids. By having more than 2 kids, each couple is increasing the size of the next generation. This means there will be a higher percentage of young people compared to the previous generation. As those kids reach reproductive age, there will be more people at that stage compared to the amount there were at that stage in the previous generation. If the fertility rate is still high, that generation will produce more individuals than they have in there own. In this way, a high fertility rate has an impact on future growth.

4. Your low fertility rate country might have had a more oval-shaped curve with high population in middle age groups. This is especially exaggerated if the fertility rate is below 2.00. Explain why low fertility rate leads to lots of middle-aged people.
-> If the reproductive age group has less on average than 2 kids per couple, they are going to leave the next generation with few people than they have. If this trend continues, the middle aged group will always be larger than the younger generations.

5. Write ten adjectives or descriptive phrases for what you might expect life, people's attitudes, conditions on the streets, etc. will be like in each of those situations. Imagine a situation with lots of middle-aged and older people in the population and write ten quick "brain-storm" descriptors for you think it would be like (Prescott, Arizona?). Then do the same for a situation with lots of children in the population.

Lots of middle age/older: working, traveling, comfortable, expendable income, free time, health care, health check ups, nursing homes, hip replacements, obituaries

Lots of children: daycare, poor, one income families, schools, errands, sharing ideas, screaming, playing, giving, hungry

Compendium Review Unit 4 Major Topic: Human Landscapes

2008-07-13T07:05:00.032-07:00

I. Human Evolution
A. Origin of Life
B. Biological Evolution
C. Classification of Humans
D. Evolution of Hominids
E. Evolution of Humans
II. Global Ecology and Human Interferences
A. The Nature of Ecosystems
B. Energy Flow
C. Global Biogeochemical Cycles
III. Human Population, Planetary Resources, and Conservation
A. Human Population Growth
B. Human Use of Resources and Pollution
C. Biodiversity
D. Working Towards a Sustainable Society

I. Human Evolution
A. Origin of Life chemical evolution
1. The primitive Earth
a. early Earth's atmosphere different than today's
b. atmosphere formed by gases escaping from volcanoes
c. atmosphere made up of H2O, N2, CO2, small amounts of H2, CO
d. water only existed as gas until Earth cooled, it rained forming oceans
2. Small organic molecules
a. rain washed gases into oceans
b. many sources of energy: volcanoes, meteorites, radioactive isotopes, lightning, ultraviolet radiation
c. energy + primitive gases react to produce small organic cmpds = nucleotides, amino acids (demonstrated in closed sys by Stanley Miller 1953)
3. Macromolecules new small organic molecules joined=macromolecules
a. RNA-first hypothesis - RNA as substrate and enzyme
b. protein-first hypothesis - amino acids joined to form microspheres
4. The protocell
a. microsphere + lipids = lipid-protein membrane
b. formation of protocell, probably a heterotroph & fermenter
5. The true cell
a. RNA-first hypothesis - genes of RNA specified protein synthesis (enzymes), enzymes used RNA to form DNA
b. protein-first hypothesis - proteins evolved enzymatic ability to synthesize DNA from nucleotides in ocean, DNA then specifies protein synthesis
Figure 22.1 illustrates chemical evolution. The following table from Professor Frolich's presentation lists some of the major events in Earth's history.B. Biological Evolution
1. Common descent
a. Charles Darwin - naturalist - theory of evolution
b. fossil evidence supports evolution
i. examples: traces - trails, footprints, burrows, worm casts, droppings; fossils - bone, impressions of plants, insects trapped in amber
ii. sediment -> strata - allows dating of fossils
iii. fossil record - most direct evidence that evolution has occurred, shows life has progressed from simple to complex (prokaryote->eukaryote->multicellular organism
c. biogeographical evidence - migration of ancestral species to isolated geographies allows evolution into different species
d. anatomical evidence - common descent hypothesis explains anatomical similarities among organisms of different species, despite functional differences
i. homologous structures - evidence of relatedness between organisms
ii. analogous structures
iii. vestigal structures - more evidence of common descent
iv. similarities in embryological development - eg paired pharyngeal pouches, postanal tail
Figure 22.6 from the text shows homologous structures.
e. biochemical evidence - same basic biochem molecules across almost all living organisms: DNA, ATP, enzymes, same triplet code in DNA, same 20 amino acids
2. Intelligent design
a. idea that diversity of life had to arise from the involvement of an "intelligent agent"
b. can not be tested in a scientific way
3. Natural selection - Darwin
a. described a mechanism for adaptation
b. variation - physical characteristics passed down to next generation
c. competition for limited resources - because of limited resources, not all individuals in a population survive
d. adaptation - those characteristics that give advantage to secure resources will be passed down to next generation. Over time, environment selects for the better-adapted traits
e. accounts for great diversity in life
Figure 22.9 from the text contrasts Jean-Baptiste Lamarck's process of acquired characteristics with Charles Darwin's process of natural selection.
C. Classification of humans
1. DNA data and human evolution
a. DNA/rRNA/protein sequencing data used compare and determine relatedness between species
2. Humans are primates adapted to arboreal life
a. mobile forelimbs and hindlimbs - easy grasping
b. binocular vision - accurate focusing
c. large, complex brain - sight, good hand-eye coordination
d. reduced reproductive rate - 1 birth at a time, extended junvenile dependency, learned behaviors, complex social interactions
3. Comparing human skeleton to the chimpanzee skeleton
a. human-spine exits center of skull-places skull in midline of body, chimpanzee-spine exits rear of skull
b. human spine s-shaped-trunk's center of gravity squarely over feet, chimp spine-slight curve
c. human pelvis & hip joint broader-no swaying when walking, chimp-narrow
d. human neck of femur longer-femur angles in at knees, chimp-femur angles out
e. human knee joint larger-supports body weight, chimp-smaller
f. human big toe not opposable, foot has arch-allows long walking and running, chimp opposable toe
D. Evolution of Hominids
1. The first hominids
a. first hominids and apes divereged from common ancestor - at time of divergence, genes and proteins of two lineages very similar
2. Hominid features
a. bipedal posture
b. shape of face- flatter face, more pronounced chin - human jaw shorter, smaller, l
i. flatter face, more pronounced chin b/c human jaw is shorter
ii. smaller, less specialized teetch
iii. larger brain
Figure 22.13 from the text shows the evolution of primates
3. Earliest fossil hominids
a. fossils found that date back to the time of ape and human lineage split
b. date between 7mya and 5mya
4. Evolution of autralopithecines
a. marks the earnest beginning of the hominid line of descent
b. gracile (slender) and robust (powerful) types
Figure 22.14 from the text shows a reconstruction of Lucy, the australopithecine, and footprints of A. afarensis.
5. Southern Africa
a. Australopithecus africanus - gracile type dated 2.8 mya
b. A. robustus - 2 to 1.5 mya
c. both walked upright, limb proportions apelike
6. Eastern Africa
a. 250 fossils of hominid A. afarensis - Lucy - found by Donald Johanson
b. walked bipedally
c. example of mosaic evolution (small apelike brain with bipedal ability)
E. Evolution of Humans
1. Early Homo
a. Homo habilis - 2.0-1.9mya, omnivores, used tools, cooperative hunting, hunters and gatherers shared food
b. Homo erectus (Asian form?)
i. larger brain, flatter face, nose projected - compared to H. habilis
ii. Homo ergaster (African form) - taller, robust, heavily musculed skeleton, small birth canal
iii. first to use fire, more advanced tools
Figure 22.15 from the text shows human evolution.
Figure 22.16 from the text show the skeleton of a 10 year old boy of the species Homo ergaster.2. Evolution of modern humans
a. multiregional continuity hypothesis
b. out-of-Africa hypothesis
3. Neandertals 200,000 years BP
a. massive brow ridge, nose, jaw, teeth protruded, low & sloping forehead, lower jaw lacked a chin
b. brain larger than Homo sapien's, maybe to control extra musculature
c. culturally advanced - built houses, used many tools & fire, buried dead
Figure 22.18 from the text illustrates how Neandertals may have looked and lived.
4. Cro-Magnons
a. oldest fossils to be designated Homo sapiens
b. entered Asia and Europe from Africa 100,000 yrs BP
c. DNA very different from Neandertal DNA - Neandertals probably cousins to Homo sapiens
d. made advanced tools (compound), experienced hunters may have caused extinction of larger animals
e. hunted cooperatively, women remained home with children
f. first to have language
g. culture included art
Figure 22.19 from the text illustrates the Cro-Magnons.
5. Human variation
a. humans geographically distributed
b. body shape and environment
i. cold temps - short limbs (Allen's rule), bulkier build (Bergmann's rule)
ii. warm temps - elongated limbs, slighter build
c. genetic evidence for a common ancestry
i. genetic differences in mDNA between different ethnic groups low - support out-of-Africa hypothesis

Definitions from Chapter 22 can be found here.

II. Global Ecology and Human Interferences
A. The Nature of Ecosystems
1. Ecosystems
a. tropical rain forest - at equator, large evergreen, broad-leaved tree
b. savanna - tropical grassland supports grazing animals
c. temperate grasslands (less rain than) temperate forests (trees lose leaves during winter)
d. desert - little water, no trees
e. taiga - very cold, norther coniferous forest
f. tundra - borders North Pole, very cold, long winters, permafrost
g. freshwater aquatic ecosystem - standing water (lakes, ponds), running water (rivers, streams), marshes where rivers meet sea
h. saltwater aquatic ecosystem - oceans, have coral reefs
Figure 23.1 from the text show the major terrestrial ecosystems.
Figure 23.2 from the text shows the major aquatic ecosystems.
2. Biotic components of an ecosystem
a. autotrophs (producers)-use inorganic nutrients plus energy source to produce organic nutrients, for self & for other members of community. Algae & plants
b. hetertroph (consumers) - need a source of organic nutrients
i. herbivores
ii. carnivores - primary, secondary, tertiary consumers
iii. omnivores
iv. detritus feeders - feed on detritus (decomposing particles of organic matter), break down dead organic matter & release inorganic substances that are taken up by plants. eg: earthworms, termites, ants, bacteria, fungi
Figure 23.3 shows some examples of bitotic components.
3. Energy flow and chemical cycling
a. most ecosystems require continual supply of energy from the sun
b. as organic nutrients are passed up the food chain, a smaller percentage of nutrients is available to higher-levels>
Figure 23.4 from the text illustrates energy flow and chemical cycling.
B. Energy Flow
1. Trophic levels
a. trees - producers - first trophic level
b. first series of animals eating trees - primary consumers - second trophic level
c. next group of animals - secondary consumers - third trophic level
2. Ecological pyramids
a. illustrates loss of 90% of energy between trophic levels.
b. therefore, few carnivores can be supported in food web
C. Global Biogeochemical Cycles
1. The water cycle
a. evaporation, precipitation, transpiration, gravity=water returns to sea, runoff, aquifers
b. human activities
i. withdraw water from aquifers
ii. clear vegetation from land, build roads, building - prevent percolation and increase runoff
iii. interfere with natural processes that purify water, add pollutants
Figure 23.9 from the test illustrates the hydrologic cycle.
2. The carbon cycle
a. CO2 in atmosphere is exchange pool for carbon cycle
b. plants take up CO2 - thru photosynthesis incorporate carbon into nutrients
c. carbon is returned to atmosphere as CO2 through respiration by organisms
d. CO2 in air combines with H2O to produce HCO3 bicarbonate ion. Source of carbon for algae
e. CO2 given off by aquatic organisms becomes bicarbonate ions
f. reservoirs for carbon=living & dead organisms, fossil fuels
g. human interference = burning of fossil fuels, destruction of forests puts more CO2 into atmosphere than is being used up
h. greenhouse gases allow solar radiation to pass thru but hinder the escape of infrared rays back into space
Figure 23.10 from the text illustrates the carbon cycle.
3. The nitrogen cycle
a. nitrogen fixation - N2->NH4 (form of nitrogen plants can use, by cyanobacteria and free-living bacteria in soil
b. nitrification - N2->NO3, needs high energy source, NH4->N02 by by soil bacteria, NO2->NO3
c. assimilation
d. denitrification
e. human interferences - N2 fertilizers, runoff causes overgrowth of algae, rooted aquatic plants.
f. acid deposition from burning fossil fuels: nitrogen oxides and sulfur dioxide enter atmosphere, combine w/water vapor to form acids
g. smog - nigrogen oxides and hydrocarbons combined
Figure 23.12 from the text illustrates the nitrogen cycle
4. The phosphorus cycle
a. phosphorus trapped in sediments moves to land after geological movement
b. weathering of rocks places phosphate ions into soil
c. plants use some (phospholipids, ATP, nucleotides)
d. animals eat producers, incorporate phosphate into teeth, bones, shells
e. death and decay make phosphate ions available to producers again
f. phosphate runoff into aquatic ecosystems, algae acquire some
g. humans boost supply by mining, runoff from fertilizer, animal waste, sewage planst results in cultural eutrophication of waterways
Figure 23.15 from the text illustrates the phosphorus cycle.
Figure 23.16 lists sources of surface water pollution.

Definitions for Chapter 23 can be found here.

III. Human Population, Planetary Resources, and Conservation
A. Human Population Growth
1. The MDCs - more developed countries
a. growth rate as a whole .1%, down from 1850-1950 when the population doubled
b. US growth rate .6%, immigrants, baby boom
c. total population expected to be at 1.2 billion by 2050
2. The LDCs - less-developed countries
a. growth rate at 1.6%
b. by 2050, population expected to jump from 5 to 8 billion
2. Comparing age structure
a. 3 age groups: prereproductive, reproductive, postreproductive
b. LDCs growth will continue, more young women in reproductive years
c. other than the US, MDCs have a stabilized age-structure diagram
Figure 24.1 from the text shows the human population growth.
Figure 24.2 shows the age-structure diagrams for MDCs and LDCs.
B. Human Use of Resources and Pollution
1. Land
a. beaches and human habitation - people like to live near the coastline - a place for fish spawning, habitats for terrestrial species, protection for coastal areas during storms
b. semiarid lakes and human habitation - humans allow animals to overgraze, they clear the land, use for fuel, fodder, water then runs off instead of being aborbed by remaining plants or replenishing wells, land becomes lifeless desert=desertification
c. tropical rain forest and human habitation - deforestation in tropical rain forests can cause desertification, loss of biodiversity
2. Water
a. increasing water supplies
i. dams - provide water, electricity. Rivers not making it to oceans, water loss to evaporation & seepage to rock beds, increase salinity, silt buildup
ii. aquifers - rain collected over hundreds of thousands of years ago, resource depletion - causes subsidence, sinkholes, saltwater intrusion
b. conservation of water - drought, salt-tolerant crops, drip irrigation, industries adopting conservation measures
3. Food food supply has increased since the 50s
a. modern/harmful farming methods - monoculture, fertilizers (production energy intensive, water pollution, kills good soil bacteria), irrigation, fuel consumption
b. positive practices - polyculture, contour farming, no-till
c. soil loss and degradation - erosion of topsoil (richest soil), sediment ends up in lakes and streams
d. green revolutions - varieties developed to yield more for in LDCs required same amount of fertizlier, water, pesticides, genetic engineering
e. domestic livestock - accounts for much pollution associated w/farming. 2/3 of cropland in US devoted to grow feed livestock. Much energy required to make food to feed livestock
Figure 24.10 from the text shows several methods of conservation.

4. Energy
a. nonrenewable sources - nuclear power, fossil fuels
b. burning of fossil fuels emites gases - rising temps threaten melting of glaciers, habitats threatened
c. renewable sources - hydropower, geothermal energy, wind power, solar
d. solar-hydrogen - using solar power to extract hyrdogen from water via electrolysis. Hydrogen can then be used as a clean-burning fuel
Figure 24.12 from the text shows 4 types of renewable energy sources.
5. Minerals
a. eg. fossil fuels, nonmetallic raw materials (sand, gravel, phosphate), metals (aluminum, copper, iron, lead, gold)
b. harmful to humans - heavy metals: lead, mercury, arsenic, cadmium, tin, chromium, zinc, and copper. Used to make batteries, electronics, pesticides, medicines, paints, inks, dyes
c. hazardous wastes - contributed by the consumption of minerals
d. 4 most common heavy metal contaminants - lead, arsenic, cadmium, chromium
e. 5 most common synthetic organic cmpds - trichloroethylene, toluene, benzene, polychlorinated biphenyls (PCBs), and cloroform.
f. synthetic organic chemicals - halogentaed hydrocarbons, used in production of plastics, pesticides, cosmetics, coatings, solvents...Chlorofluorocarbons (CFCs) - thinning of Earth's ozone. MDCs no longer use.
C. Biodiversity
1. Loss of biodiversity
a. habitat loss due to human interference
b. alien species
c. pollution - acid deposition, global warming, ozone depletion, synthetic organic chemicals
d. overexploitation
e. disease
2. Direct value of biodiversity
a. medicinal value - rosy periwinkle, penicillin, limulus in blood of horseshoe crab
b. agricultural value - natural predators, pollinators
c. consumptive use value - aquatic organisms, wild fruits, vegetables, trees
3. Indirect value of biodiversity
a. waste disposal - decomposers extremely useful to humans
b. provision of freshwater - after a storm forests soak up water and then release over a long period of time, preventing flooding
c. prevention of soil erosion - deforestation causes erosion, erosion causes silt buildup in dams and ecosystems
d. biogeochmeical cycles - keeps excess pollutants in environment under control
e. regulation of climate - trees provide shade, take up CO2, when cut, they release CO2, contributing to global warming
f. ecotourism
Figure 24.17 from the text provide examples of the direct benefits of wildlife.
D. Working Toward a Sustainable Society
1. Today's sustainable society
a. overpopulation of LDCs and overconsumption by MDCs both account for increasing poullution and extinction of wildlife
b. land used for human purposes
c. agriculture - big use of fossil fuels, use of pesticides, create pollution, use of freshwater
d. demand on freshwater
e. growing demand on energy sources
2. Characteristics of a sustainable society
a. use renewable energy
b. recycle materials
c. protect natural ecosystems
d. efficiency
e. rural sustainability - preserve ecosystems, cover crops, multiuse farming, composting, low flow or trickle irrigation, cultivars, precision farming, integrated pest management, plant variety of species, multipurpose trees, protect wetlands, buy local
f. urban sustainability - energy efficient transportation sys, solar/geothermal energy, green roofs, improve storm water mgmt, plant native grasses, greenbelts, revitalize old sections before developing new, control light and noise pollution, encourage recycling
3. Assessing economic well-being and quality of life
a. GNP - strictly economic
b. ISEW (index of sustainable economic welfare) - takes into account forms of value in addition to monetary value (environmental damage, natural resource depletion, distributional equite etc)
c. GPI (genuine progress indicator) - considers quality of life
d. use value, option value, existence value, aesthetic value, cultural value, scientific & educational value
Figure 24.18 from the text shows several unsustainable activities.

Definitions from Chapter 24 can be found here.

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Unit 4, Online Lab #1: Embryonic & Fetal Development

2008-07-11T13:48:00.007-07:00

LIST OF TEN SIGNIFICANT EVENTS DURING EMBRYONIC AND FETAL DEVELOPMENT
--quick description of what the event is
--when (hour, week, day or month) during development when it occurs
--why you think it is significant
--image or photo of that event or stage for five of the events

Fertilization
description: Union of egg and sperm in the oviduct
timing: 0 to 24 hours post-ovulation
significance: A required step. Many steps leading up to fertilization must occur for it to be successful. Many things can go wrong preventing its occurrence.

Cleavage
description: Duplication division.
timing: 1.5 to 3 days post-ovulation
significance: It is the first instance of mitotic cell division. All daughter cells receive the full 46 chromosomes.

Blastocyst
description: The morula moves down from the oviduct into the uterus. Cells flatten and form a hallow cavity. The flattened cells form an inner cell mass. The structure is now called a blastocyst.
timing: 4 days post-ovulation
significance: The cells that make up the inner cell mass will later become the embryonic disk. The outer cells walls will become the chorion. The chorion will contribute to the formation of the placenta.

Implantation
description: The blastocyst continues down into the uterus and secretes enzymes that allow it to implant in the uterine wall.
timing: 5 to 8 days post-ovulation
significance: A required step. Without implantation, the pregnancy will not continue.

Embryonic disk
description: Formation of embryonic disk
timing: 8 to 12 days post-ovulation
significance: Marks the start of gastrulation. The embryonic disk will later form the primary germ layers.

Primary germ layers
description: The embryonic disk forms tissue layers called the primary germ layers.
timing: 13 days post-ovulation
significance: All of the organs and tissues in an adult human can be traced back to the 3 primary germ layers, ectoderm, mesoderm, and endoderm.

Nervous system / heart
description: The nervous system becomes visually evident. Development of the heart begins.
timing: 21 to 23 days post-ovulation
significance: The nervous system will continue to develop leading to reflexes that are required for survival later in life. The heart will continue to develop allowing oxygen rich blood to reach tissues and organs

Bones
description: Cartilage starts to be replaced by bones.
timing: 3rd month
significance: The skeleton contributes to so many important functions: movement, support, protection, production of red blood cells, storage of minerals and fat.

Movement
description: The mother begins to feel movement.
timing: 5th to 7th month
significance: Although the fetus will begin moving sooner (which is equally important), this is an important moment for the mother. A potentially life changing experience.

Lungs
description: The lungs are capable of breathing air.
timing: 23 to 26 weeks post-ovulation
significance: The surfactant secreted by the lungs prevents them from sticking together. If born premature, the lungs of a child born at this stage can perform gas exchange.

Compendium Review Unit 4 Major Topic: Reproduction

2008-07-10T12:46:00.021-07:00

I. Reproductive System
A. Human Life Cycle
B. Male Reproductive System
C. Female Reproductive System
E. Female Hormone Levels
F. Control of Reproduction
G. Sexually Transmitted Diseases
II. Development and Aging
A. Fertilization
B. Pre-Embryonic and Embryonic Development
C. Fetal Development
D. Pregnancy and Birth
E. Development after Birth

I. Reproductive System
A. Human Life Cycle
1. Functions of reproductive organs
a. production
b. transport
c. delivery
d. fertilization, nourishment
e. hormones
2. Mitosis and meiosis
a. mitosis - duplication division for growth and repair, diploid # 46 chromosomes
b. meiosis - reduction division, to produce sex cells, haploid # 23 chromosomes
B. Male Reproductive System
1. Organs - testes, epididymides, vasa deferentia, seminal vesicles, prostate gland, urethra, bulbourethral glands, penis - see definitions for functions
Figure 16.2 from the text illustrates the male reproductive system
2. Orgasm in males
a. nitric oxide release leads to production of cGMP (cyclic guanosine monophosphate)
b. cGMP cuases smooth muscle of incoming arterial walls to relax
c. erectile tissue fills with blood
d. outgoing venous walls compress, erection
e. sperm enter urethra from each vas deferens, glands contribute secretions
3. Male gonads, the testes
a. seminiferous tubules - location of spermatogenesis, Sertoli cells
b. interstitial cells - lie between seminiferous tubules, secrete androgens
Figure 16.4 from the text depicts the testis and sperm and spermatogenesis.
4. Hormonal regulation in males
a. hypothalamus secretes GnRH
b. GnRH stimulates anterior pituitary to secrete gonadotropic hormones (FSH, LH)
c. GnRH, FSH, LH involved in neg feedback relationship - maintains constant production of sperm and testosterone
C. Female Reproductive System
1. The genital tract
a. egg - ovary->fimbriae->cilia/oviduct->uterus, lives 6-24 hrs unless fertiized
b. fertilization (zygote formation) usually takes place in oviduct
c. implantation after several days
d. uterus, endometrium, cervix, vagina
Figure 16.6 from the text illustrates the female reproductive system.
2. External genitals vulva: labia majora, mons pubis, labia minora, glans clitoris, urethra, vagina
3. Orgasm in females
a. labia minora, vaginal wall, clitoris engorge with blood
b. blood vessels in vaginal wall & mucus-secreting glands beneath labia minor secrete lubricating fluid
D. Female Hormone Levels
1. Ovarian cycle (phases): nonpregnant
a. hypothalamus secretes GnRH
b. GnRH stimulates anterior pituitary to secrete gonadotropic hormones (FSH, LH)
c. FSH & LH not present in constant amounts, secreted at different rates during cycle
d. follicular phase - FSH promotes development of follicles that secrete estrogen
e. estrogen level in blood provides neg feedback to ant pituitary secretion of FSH - ends follicular phase
f. spike in estrogen - large amt of GnRH secreted - surge of LH - ovulation day 14
g. luteal phase - LH promotes development of corpus luteum - secretes progesterone
Figure 16.8 from the text illustrates the ovarian cycle and shows oogenesis.
2. Estrogen and progesterone
Figure 16.10 from the text shows the female hormone levels during a complete menstrual cycle (no pregnancy).
3. Uterine cycle: nonpregnant
4. Fertilization and pregnancy
a. fertilization occurs in oviduct
b. pregnancy begins when developing embryo implants in endometrium
c. placenta produces HCG which stimulates corpus luteum to produce more progesterone
d. progesterone shuts down hypothalamus & anterior pituitary - prevent new follicles from beginning
Figure 16.11 shows the effect of pregnancy on female hormone levels.
E. Control of Reproduction
1. Birth control methods
a. abstinence
b. contraceptives - birth control pill, IUD, diaphragm, female & male condums, implants, injections, vaccines
c. vasectomy and tubal ligation
d. morning after pills
2. Infertility
a. causes
i. male - low sperm, abnormal sperm=temperature, sedentary, smoking, alcohol
ii. female - body weight=small follicles; blocked oviducts=pelvic inflammatory disease, endometriosis
b. assisted reproductive technologies
i. artificial insemination by donor (AID), intrauterine insemination (IUI)
ii. in vitro fertilization (IVF)
iii. gamete intrafallopian transfer (GIFT)
iv. surrogate mothers
v. intracytoplasmic sper injection (ICSI)
F. Sexually Transmitted Diseases
1. STDs caused by viruses
a. HIV infections - primary host is helper T lymphocyte, immune system becomes severly impaired, treatment=HART
b. genital warts caused by human papillomaviruses
c. genital herpes caused by herpes simplex virus
d. hepatitis infects the liver
2. STDs caused by bacteria
a. chlamydia (chlamydia trachomatis) - burning during urination, mucoid discharge
b. gonorrhea (neisseria gonorrhoeae) - pain upon urination, greenish yellow urethral discharge, can spread to eyes, mouth throat
c. syphilis (treponema pallidum) - chancre, rash, affects cardiovascular sys
3. Two other infections
a. bacterial vaginosis (gardnerella vainalis)
b. trichomonas vainalis, candida albicans

Definitions for Chapter 16 can be found here.

II. Development and Aging
A. Fertilization
1. Steps of fertilization
a. egg plasma membrane - zona pellucida (extracellular matrix), corona radiata (follicular cells)
b. sperm penetrate zona pellucida, 1 enters cell after acrosome forges pathway through zp, sperm and egg membranes fuse
c. upon sperm touching egg, egg's plasma membrane depolarizes
d. only sperm nucleus fuses to egg
Figure 17.1 from the text illustrates the steps of fertilization.
B. Pre-Embryonic and Embryonic Development
1. Processes of development
a. cleavage - mitotic cell division, no increase in size, each cell rcvs full complement of chromosomes and genes
b. growth - cell division accompanied by increase in size of daughter cells
c. morphogenesis - shaping of embryo, certain cells migrate in relation to other cells
d. differentiation - cells take on specific structure and function, 1st sys to become visibly differentiated is nervous sys
2. Extraembryonic membranes named for function in shelled animals
a. chorion - develops into fetal half of placenta - provides nourishment, oxygen, removes waste, blood vessels w/in chorionic villi - continuous w/umbilical blood vessels
b. allantois - collects urine, later becomes bladder, its blood vessels become umbilical blood vessels (umbilical arteries - O2 poor, umbilical veins - O2 rich)
c. yolk sac - first embryonic membrane to appear, contains many blood vessels, first site of blood cell formation
d. amnion - enlarges w/embryo/fetus, fluid cushion
Figure 17.2 from the text illustrates the extraembryonic membranes.
3. Stages of development
a. pre-embryonic development - first week, zygote->morula->blastocyst
Figure 17.3 from the text illustrates pre-embryonic development.b. embryonic development - 2nd wk
i. implantation chorion secretes enzymes and HCG
ii. HCG serves to maintain corpus luteum-> secretes progesterone so endometrium maintained (no menstruation)
iii. inner cell mass via gastrulation-> embryonic disk, yolk sac, & amniotic cavity
iv. primary germ layers formed from embryonic disk
c. embryonic development - 3rd wk
i. nervous sys - first to be visible
ii. heart development begins
d. embryonic development - 4th & 5th wk
i. body stalk connects embryo to chorion
ii. allantois in body stalk
iii. head and tail lift, body stalk moves anteriorly => umbilical cord
iv. limb buds appea
v. head enlarges, sense organs become more prominent, eyes, ears, nose apparent
Figure 17.6 from the text shows and illustrates a human embryo at the beginning of the fifth week.
e. embryonic development - 6th thru 8th weeks
i. embryo changes to form that resembles human being
ii. neck region develops, head in normal relationship with body
iii. nervous sys development allow reflex actions
Figure 17.4 from the text illustrates the stages of embryonic development.
Figure 17.5 from the text illustrates the course of development for the 3 primary germ layers.
C. Fetal Development
1. functions of progesterone & estrogen during pregnancy (source is placenta)
a. neg feedback on hypothalamus & anterior pituitary - prevent new follicles from maturing
b. maintain endometrium - no menstruation
2. Path of fetal bloodexchange of nutrients, oxygen, wastes is across chorionic villi
Figure 17.7 from the text shows the path of fetal cirulation.
3. Events of fetal development
a. 3rd and 4th months
i. head growth slows
ii. hair develops
iii. cartilage gets replaced by bone
iv. distinguish male from female
v. heartbeat heard with stethoscope
b. 5th through 7th months
i. movement felt by mom
ii. fetal position
iii. eyelids open
iv. lanugo & vernix caseosa
c. 8th through 9th months
i. weight gain 1 lb per week
ii. fetus rotates, head pointed down
4. Development of male and femal genitals differentiation depends on hormones present
a. normal development of the genitals
i. internal genitals - gonads develop during 7th wk
ii. prior to 7th wk, males & females both have Mullerian & Wolffian ducts
iii. external genitals
iv. small bud, urogenital groove
b. abnormal development of the genitals
i. presence or absence of SRY gene can cause XY female or XX male syndrome
ii. SRY gene causes testes to form, testes secrete: testosterone, anti-Mullerian hormone, dihydrotestosterone
iii. ambiguous sex determination - androgen insensitivity syndrome (plasma membrane receptors for testosterone ineffective), male pseudohermaphroditism
Figure 17.9 from the text illustrates the development of the internal and external genitals in males and females.
D. Pregnancy and Birth
1. energy level fluctuates, increase in weight
2. progesterone - relaxes smooth muscle-uterus & arterial walls, low blood pressure: renin-angiotensin-aldosterone mechanism by estrogen
a. aldosterone - sodium, water intake, blood volume increases 40%
b. increase in red blood cells, cardiac output increases 20-30%
3. Pulmonary values increase
a. increase in uterus size pushes internal organs superiorly, widens thoracic cavity
b. carbon dioxide levels fall - concentration gradient favorable to flow of CO2 from fetal blood
4. Other effects
a. enlargement of uterus compresses bladder and ureters
b. compression of inferior vena cava - decreases venous return=> edema varicose veins
c. placent produces peptide hormones - one makes cells resistant to insulin
d. striae gravidarum, darkening of skin
5. Birth
a. positive feedback - cervix stretches - causes uterine contractions & release of oxytocin from posterior pituitary gland
b. oxytocin stimulates uterine muscles
c. uterine contractions push fetus down, cervix stretches more cycle continues
6. Stage 1
a. effacement - cervical canal slowly disappears, babies head acts as wedge to assist cervical dilation
7. Stage 2
a. contractions - 1 minute each, 1-2 minutes apart
b. back of head faces up
c. episiotomy
d. umbilical cord cut & tied
8. Stage 3
a. afterbirth expelled
Figure 17.11 from the text shows the birthing process.
E. Development after Birth
1. Hypotheses of aging
a. genetic in origin - mitochondrial hypothesis of aging
b. whole-body process - changes to hormonal system, immune system, changes to tissue
c. extrinsic factors - diet, exercise, habits
2. Effect of age on body systems
a. skin - becomes thinner & less elastic; less adipose tissue in subcutaneous layer; sagging, wrinkling caused by loss of thickness. fewer sweat glands - skin cracks, fewer hair follicles
b. processing and transporting
i. heart shrinks, reduced cardiac output
ii. arteries harden, blood pressure rises over time
iii. blood flow to liver reduced, drugs not metabolized as efficeiently - lower doses required
iv. blood supply to kidneys reduced
v. loss of teeth
c. integration and coordination
i. loss in short-term memory, but can learn and remember new material
ii. neuron death may be due to reduced blood flow
iii. reaction time slows, more stimulation needed for senses
iv. hearing impacted
v. loss of skeletal muscle, reduction of bone density
d. the reproductive system
i. menopause, andropause

Definitions for Chapter 17 can be found here.

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Unit 3 Ethical Essay: Exercise

2008-07-09T18:00:00.006-07:00

Get Out

How can it be? Exercise facilities seem to be popping up on every corner. But you don't need to be an expert to know that obesity is on the rise in our country, not only in adults but in children as well. So why is it on the rise? Because of the way we view exercise.

To start, what does exercise mean? Does it mean dragging yourself to the gym every day and plopping yourself on a treadmill for 20 minutes while you watch TV or read a magazine? Or does it mean throwing a dvd into your player at home and doing 30 minutes of cardio-kickboxing? Neither sounds like much fun to me. How does going for a walk with your spouse sound? Or pushing your kids on the prairie path in the stroller? Maybe today you ride your bike to the video store instead of driving. Then maybe tomorrow you take a walk up into the mountains to get some fresh air and take in a great view. We need to change our perspective on what it means to get exercise.

Secondly, there are a few problems with using exercise - especially exercise at a gym - as a means to achieve the goal of weight loss. First, what happens when you reach your goal? Do you stop exercising? Do you end your membership? Is it fun to be inside, when the weather is beautiful outside? I don't think so. And is exercise fun when the whole point of it is to lose weight? Probably not. Instead of using just weight loss as a goal, what about combining it with things like:

Tomorrow I am going to walk the same distance, but I am going to do it 1 minute faster.
OR
Tomorrow I am going on my hike except I am going to walk 5 minutes past the point where I turned around today.

As you reach these goals, set new ones. And what about combining these small specific goals with more geneneral goals: I want to feel healthy. I want to my lungs to burn a little. I want to feel the burn of lactic acid in my muscles and tomorrow I want my muscles to ache a little. I want to feel invigorated by the cold morning air. I want to feel strong.

Lastly - if at all possible - exercise needs to be a family event and it needs to be outside! The obesity problem in our nation's children is not going to improve unless they learn from their parents the importance of living a healthy lifestyle. There are so many wonderful ways to give your body a workout in the great outdoors. While you are outside getting some exercise, your children can be learning to appreciate the importance and greatness of our National Parks. Especially in the Prescott area, we are so blessed with 1.25 million acres of acres of beautiful National Forest land. And unlike a gym membership, when you excercise outside - you can get in a good workout - for free.
.
So there you have it. We need to change our view about exercise. Forget the gym. Get outside and take your kids. Take in the view. Make it a priority in your family. If you need to lose weight, combine that goal with small specific and big, broad goals. Your body will be happy.

Unit 3 Lab Project: Build a Movable Limb

2008-07-07T11:20:00.027-07:00

INTRODUCTION:

The purpose of this lab was to
1. Create a movable limb
2. To demonstrate how muscle action is initiated
3. To demonstrate the process by which the muscle actually contracts

These 3 items were to be built using regular household items. I ended up using 4 models to demonstrate all of the details that were required.

MODEL:
Limb parts listed with materials that represent each.

Movable Limb
Biceps brachii - artificial evergreen branch
Humerus - cinnamon stick
Radius - cinnamon stick
Ulna - cinnamon stick
Capitulum - small, sparkly gold ball covered with masking tape
Trochlea - small gold bell covered with masking tape

Materials:

Building the limb:

A movable limb - as the biceps brachii contracts, the radius (along with the ulna) moves toward the humerus:

Muscle fiber with axon
Sarcolemma - purple plastic wrap
T tubule - thin green paper-coated wire
Myofibrils - glue sticks
Axons - brown pipe cleaners
Schwann cells - oval wooden beads

Materials:

Building the muscle fiber and axon:

The muscle fiber with axons:

Note: After uploading this image, I realized I made a mistake on this one. I should have had one axon with several axon terminals reaching to the 2 muscle fibers.

Lastly, a basic image of one myofibril showing how the individual sarcomeres line up along the length of it:

Sarcomere
Myosin - artificial evergreen limb with masking tape around the center
Myosin head - artificial evergreen needle
Actin - natural jute rope
Troponin - cloth rose
Tropomyosin - gold bead rope
Sarcoplasmic reticulum - green jute rope
Calcium ions - red hearts

Materials:

Building the sarcomere:

The sarcomere:

The sarcoplasmic reticulum in close vicinity to the sarcomere. In the photo on the left, calcium is stored in the sarcoplasmic reticulum. The photo on the right shows the release of the calcium ions from the sarcoplasmic reticulum:

Calcium ions combine with troponin on actin:

Myosin heads attach to actin in the photo on the left. In the photo on the right, the power stroke of the myosin heads moves the actin filaments past the myosin filaments. In this way, the actin filaments approach one another and the sarcomere shortens. As the sarcomeres of a myofibril shorten, the myofibril shortens. This is how a muscle contracts:

Action potential
Axonal membrane - wooden blocks
Sodium ions - white textured balls
Potassium ions - wooden balls
Gated sodium ion channel - green lettered wooden blocks
Gated potassium ion channel - red lettered wooden blocks

Materials:

Resting potential:

Action potential begins as gated sodium ion channels open, sodium ions move from outside of the axon to the inside. The action potential propagates along the axon as the sodium channels open from left to right, sodium move inside the cell, and the inside of the cell changes from -65mV to +40mV. This voltage change also moves from left to right, which is the propagation of the action potential:

Action potential ends as the voltage changes back from +40mV to -65mV. This change happens as the gated potassium ion channels open to allow potassium ions to move from the inside to the outside of the axon. This voltage change also occurs from left to right along the axon:

CONCLUSION
The four models provide above detail several important functions of our body. First, the movable limb model shows how the contraction of a muscle can move a limb around a joint. Second, the model of the muscle fiber shows the basic structures that are involved with muscle contraction. It also lays the groundwork to understand how sliding of the filaments of the sarcomere result in contraction of the muscle fiber. The third model details the structures of the sarcomere and shows how calcium ions are released from the sarcoplasmic reticulum and then combine with troponin on the actin filaments. It also shows how the myosin power stroke slides the actin filaments towards each other to shorten the sarcomere. And the last model illustrates the movement of sodium and potassium ions across the axonal membrane. The movement of these ions contributes to the action potential.

Unit 3, Online Lab #2: Muscle Function

2008-07-03T14:53:00.010-07:00

INTRODUCTION:
Sitting upright. Walking. Running. Bending. Stretching. Staying warm. Distributing oxygen. From the simple to the complex, each of these activities requires muscle action. At the core of muscle action are two protein filaments, actin and myosin. Initiation starts in the nervous system and the signal to contract is trasmitted from a motor neuron to a muscle fiber by a neurotransmitter, acetylcholine (ACh). Once ACh diffuses accross the synaptic cleft and binds to receptors in the sarcolemma, an impulse is generated that spreads down into the T tubues to the sarcoplasmic reticulum (SR). This releases calcium ions from the SR, and contraction of the sarcomere is initiated.

The purpose of this lab is to understand how and why temperature and fatigue effect muscle action.

MATERIALS AND METHODS:
Here are pictures of how I performed each part of the lab.

To test the effect of temperature on muscle action, I submerged my hand in ice cold water for one minute (which hurt very bad, I must add!!).
To test the effect of fatigue on muscle action, I squeezed the green ball.
DATA:

ANALYSIS OF DATA:

1. What are the three changes you observed in a muscle while it is working (contracted)?
The relaxed muscle felt soft, the contracted muscle felt hard.
The relaxed muscle was shorter than the contracted muscle.
The circumference of the contracted muscle was larger than that of the relaxed muslce.

2. What effect did the cold temperature have on the action of your hand muscles? Explain.
After submersing my hand in cold water for one minute, I could hardly make a fist. The muscles felt slow and sluggish; it actually hurt a little. It was like the movement of my hand was not working as fast as my brain wanted it to.

3. What effect did fatigue have on the action of your hand muscles? Explain.
By the end of the first set, the speed at which I could contract started to slow down. The squeeze itself also felt alot weaker. The action slowed because my hand started to ache and cramp.

PROBLEMS WITH DATA OR TECHNIQUE:
You will notice in my data for the fatigue trials, that the number of repetitions in the fourth trial was the same as the third trial and that the number of repetitions increased in the 5 trial. This can be explained by the fact that after the fifth trial I realized that my squeezes had gotten very weak. In the sixth trial I concentrated on trying to apply the same force as the squeezes that I performed in the first trial, and noticed that it did take longer compared to when I was not concentrating as much (in the 4th and 5th trials).

I was also using as online counter to time the 20 seconds and I had to reset after each trial. This allowed some time for rest in between each trial.

CONCLUSION:
This lab showed that both temperature and fatigue impact muscle performance. After my hand was submerged in ice cold water, the movement of hand was very slow and sluggish. Similarly, after each set (and after each repetition) the movement of my hand also slowed.

In both instances, the muscles are being asked to work at sub-optimal levels. In cold temperatures, blood vessels and capillaries restrict, reducing the amount of blood flow to the area. With less oxygen being delivered to the area, production of ATP will be slowed. Without plentiful ATP, it will take longer for all of the myosin heads to return to the resting position, increasing the amount of time between power strokes. Diffusion of the ACh across the synaptic cleft probably takes longer and relase of the calcium ions takes more time as well.

The cause of the slowed action while squeezing the ball is most likely due to the buildup of lactic acid. It is toxic to cells and caused the cramping and aching that I felt. The cramping when away once I stopped squeezing and enough oxygen was delivered to the area to allow breakdown of the lactate to pyruvate.

For a visual representation of how a sarcomere contracts, I went to our book. I really like Figure 12.5. It shows the structure of a muscle fiber, and it also shows the sarcomere, in the relaxed position and in the contracted position.

The source of this image is the text for our class:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).
The digital image was downloaded from the power point presentation for Chapter 12 on the Aris website.

This image illustration shows the specific action of actin and myosin. This image was taken from the Owensboro Community & Technical College's Anatomy and Physiology I notes page.

Information in the introduction and conclusion was taken from our textbook:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Compendium Review Unit 3 Major Topic: Movement

2008-07-01T11:58:00.026-07:00

Movement

I. Skeletal System
II. Muscular System

I. Skeletal System
A. Overview of Skeletal System
1. Functions of the skeleton
a. supports the body
b. protects soft body parts (skull, rib cage, vertebrae)
c. produces blood cells
d. stores minerals and fat
e. permits flexible body movement - along with muscles
2. Anatomy of a long bone
a. diaphysis with medullary cavity - compact bone, endosteum, yellowish bone marrow
b. epiphysis - articular cartilage, spongy bone containg red bone marrow
c. periosteum - covers long bone, is continuous with ligaments and tendons
d. bone
i. compact - osteon - lacunae - osteocyte. canaliculi connect lacunae, run thru matrix
ii. spongy - trabeculae (plates) separated by unequal spaces, filled with red bone marrow. osteocytes irregular placement in trabeculae
e. cartilage - flexible, chondrocytes in irregularly grouped lacunae, no nerves or vessels
i. hyaline cartilage - firm, somewhat flexible, ends of long bones, nose, ends of ribs, larynx, trachea
ii. fibrocartilage - strong, withstand tension & pressure, disk btwn vertebrae, knee
iii. elastic cartilage - more flexible than hyaline, ear flaps, epiglottis
f. fibrous connective tissue
i. ligaments
ii. tendons
Figure 11.1 from the text shows the anatomy of a long bone.

B. Bone Growth, Remodeling, and Repair osteoblasts, osteocytes, osteoclasts
1. Bone development and growth
a. intramembranous ossification - formation of bone developed between sheets of fibrous connective tissue. eg skull
b. endochondral ossification - bone growth occurs as bone replaces the cartilaginous models of the bones
i. cartilage model - chondrocytes lay down cartilage
ii. bone collar - matrix secreted from osteoblasts calcifies, covers diaphysis
iii. primary ossificaton center - osteoblasts in interior lay down spongy bone
iv. medullary cavity & secondary ossification sites - osteoclasts abosorb spongy bone of diaphysis, creates medullary cavity. secondary site form in epiphysis
v. epiphyseal (growth) plate - band of cartilage between primary & each secondary site.
vi. final size - determined when epiphyseal plates close
c. hormones affect bone growth - growth hormone, thyroid hormone,
2. Bone remodeling and its role in homeostasis
a. keeps bone strong, 18% of bone recycled each year
b. allows body to regulate amount of calcium in blood, if blood calcium is high, it can be deposited into bone, if low, calcium removed from bones
c. parathyroid hormone - accelerates bone recycling - increases blood calcium
d. calcitonin - hormone that acts opposite to PTH
e. allows bones to respond to stress -
f. walking, jogging, weight lifting - stimulates work of osteoblasts
3. Bone repair
a. hematoma
b. fibrocartilaginous callus
c. bony callus
d. remodeling
Figure 11.2 from the text illustrates endochondral ossification of a long bone. Additional images from the text can be found here.C. Bones of the Axial Skeleton
Figure 11.7 from the text shows the bones of the human skull.
1. The skull
a. cranium - protects brain, made of 8 bones in adults, some contain sinuses: frontal, parietal, occipital, temporal, sphenoid, ethmoid
b. facial bones
Figure 11.8 from the text shows the facial bones and the hyoid bone.
2. The hyoid bone
a. only bone that does not articulate with another bone
b. attached to temporal bones by muscles & ligaments, to larynx by membrane
c. anchors tongue, site for attachment of muscles associated w/swallowing
3. The vertebral column 33 vertebrae
Figure 11.9 from the text shows the vertebral column.
a. 4 curvatures provide more resilience & strength for upright position
b. protects spinal cord, site of attachment for muscles that move the vertebral column
c. types: cervical, thoracic, lumbar, sacral, coccyx
d. intervertebral disks - fibrocartilage = padding
4. The rib cage protective and flexible
a. composed of the thoracic vertebrae, the ribs & associated cartilages, & sternum
b. the ribs - 12 pairs, all connect to thoracic vertebrae, upper 7 connect w/sternum
c. the sternum - lies in midline of body, with ribs protect heart, lungs
i. composed of manubruim, body, xipoid process
Figure 11.10 from the text shows details of the thoracic verebrae and the rib cage.D. Bones of the Appendicular Skeleton
1. The pectoral girdle and the upper limb flexibility
Figure 11.11 from the text shows the bones of the pectoral girdle and the upper limb.
a. pectoral girdle: scapula, clavicle
b. upper limb: arm - humerus, forearm - radius, ulna, hand - carpals, metacarpals, phalanges
2. The pelvic girdle and lower limb strength
a. pelvic girdle: coxal bones
b. lower limbs: thigh - femur, leg - tibia, fibula, foot - tarsals, metatarsals, phalanges
Figure 11.12 shows the bones of the pelvic girdle and lower limb.E. Articulations
1. Joints
a. cartilaginous - connected by hyaline cartilage (costal cartilages that join ribs to sternum) or by fibrocartilage (intervertebral disks), tend to be movable
b. fibrous - many are immovable (sutures between cranial bones)
c. synovial - freely movable, contain bursa, menisci, synovial fluid
Figure 11.13 from the text shows synovial joints. Figure 11.14 illustrates synovial joint movements.

Definitions for Chapter 11 can be found here.

II. Muscular System
A. Overview of Muscular System
1. Types of muscles
a. smooth muscle fibers - spindle-shaped, uninucleated, form sheets, in walls of hollow internal organs, cause contraction (involuntary) of walls
b. cardiac muslce - forms heart wall, cells generally uninucleated, striated, tubular, branched (allowing interlocking of fibers at intercalated disks), gap junctions in plasma membrane, contraction rhythmical, involuntary
c. skeletal muscle fibers - tubular, multinucleated, striated, attached to skeleton, long - run length of muscle, voluntary
Figure 12.1 from the text shows the 3 types of muscle tissue.2. Functions of skeletal muscles
a. support the body - contraction opposes force of gravity, allows upright
b. make bones move
c. help maintain a constant body temp - heat from breakdown of ATP
d. contraction assists movement in cardiovascular and lymphatic vessels
e. help protect internal organs and stabilize joints
3. Skeletal muscles of the body
a. basic structure
i. fascicles - bundles of skeletal muscle fibers that make up a muscle
ii. connective tissue surrounds both fiber and fascicle
iii. fascia cover muscle and extend beyond muscle to become tendon
b. skeletal muscles work in pairs
i. prime mover - muscle doing most of the work, synergists - assist prime mover, antagonist - muscle that acts opposite to a prime mover
ii. origin & insertion, insertion - contracting muscle pulls on tendons at insertion
4. Names and actions of skeletal muscles
a. size - eg gluteus maximus
b. shape - eg deltoid, trapezius, latissimus, terres
c. location - eg external obliques, pectoralis, gluteus, brachii, sub
d. direction of muscle fibers - eg rectus abdominis, obicularis, trasverse, oblique
e. attachment - eg sternocleidomastoid, brachioradialis
f. number of attachments - eg biceps brachii, quadriceps femoris
g. action - eg extensor digitorum, adductor longus, flexor, masseter, levator
Figure 12.4 from the text shows the superficial skeletal muscles.B. Skeletal Muscle Fiber Contraction
Figure 12.5 shows skeletal muscle fiber structure and function.
1. Muscle fibers and how they slide
a. myofibrils and sarcomeres
i. muscle fibers->myofibrils->sarcomeres->myofilaments=actin & myosin
ii. actin - protein that makes up thin filaments (I band), attached to Z line
iii. myosin - protein that makes up thick filaments (H zone)
iv. action & myosin overlapping make up A band
b. myofilaments
i. thick filaments - several 100 molecules of myosin
ii. thin filaments - 2 intertwining strands of actin, tropomyosin, troponin
iii. sliding filaments - contraction of muscle fiber starts when calcium released from sarcoplasmic reticululm.
iv. sliding filament model - sarcomeres shorten by by actin filaments sliding past myosin filaments. actin fil. approach each other. myosin pull actin
v. ATP (broken down by myosin) supplies energy for muscle contraction
2. Control of muscle fiber contraction
a. nerve impulse reaches axon terminal, synaptic vesicles relase ACh into synaptic cleft
b. ACh binds to receptors in sarcolemma->generates impulses, spread down T tubules
c. sarcoplasmic reticulum releases Ca2+->leads to sarcomere contraction
d. Ca2+ combines with troponin, causes tropomyosin threads to shift, exposing myosin binding site on actin
e. ADP and P on myosin heads attach to actin filament
f. ADP and P are released and cross-briges bend sharply (power stroke)
g. ATP molecules bind to myosin heads, cross-bridges broken, heads detach from actin
h. ATP is hydrolyzed to ADP and P, process starts over, myosin reattaches further
along actin filament
i. cycle recurs until calcium ions are actively (requires ATP) returned to storage site in sarcoplasmic reticulum
Figure 12.6 from the text illustrates the neuromuscular junction and Figure 12.7 shows the function of calcium and myosin in muscle contraction.

C. Whole Muscle Contraction
1. Muscles have motor units
a. varying ratios of innervation - motor axons per muscle fiber (ie 1 motor neuron per 23 muscle fibers in the ocular muscles vs 1:1000 in the gastrocnemius)
b. muschel twitch - occurs when motor unit stimulation is infrequent
c. latent period, contraction period, relaxation period
d. tetanus achieved from summation of rapid series of stimuli
e. recruitment - when more and more muscle units in a muscle are activated upon increased intensity of nervous stimulation
f. muscle tone - when some motor units are always contracted, but not enough to cause movement
1. Energy for muscle contraction
a. fuel source for exercise
i. glycogen & fat stored in muscle
ii. blood glucose & plasma fatty acids
b. sources of ATP for muscle contraction, formation of ATP by:
i. creatine phosphate (CP) - anaerobic, CP pluls ADP = ATP & creatine
- CP formed only when muslce is resting, limited amt stored
- occurs in midst of sliding filaments
- used at beginning of submaximal exercise & during short-term, high-intensity exercise that lasts less than 5 seconds
ii. fermentation - anaerobic
- hormones provide signal to muscle cells to break down glycogen
- fast-acting, results in buildup of lactate
- oxygen debt required to complete metabolism of lactate
iii. cellular respiration - aerobic
- can use glucose from breakdown of glycogen, glucose taken up from blood, fatty acids
2. Fast-twitch and slow-twitch muscle fibers
Figure 12.11 shows fast- and slow-twitch muscle fibers.
a. fast-twitch fibers - (usually) anaerobic, designed for strength
i. motor units contain many fibers, explosions of energy
ii. light color b/c few mitochondria, little or no myoglobin, fewer blood vesssels
iii. vulnerable to accumulation of lactate = fatigue
b. slow-twitch fibers - (mostly) aerobic, more endurance
i. tire only when fuel supply is gone
ii. dark color b/c many mitochondria, contain myoglobin, dense capillary beds
iii. draw more blood & oxygen than fast-twitch
iv. lowe maximum tension, highly resistant to fatigue
v. steady, prolonged production of ATP when oxygen is available
3. Delayed onset of muscle soreness
a. thought to occur with any activity that causes muscles to contract while they are lengthening
b. prevention - warm up, cool down, start gradually with new activity
Figure 12.9 shows the fuel sources for muscle contraction during submaximal exercise (65-75% of effort) and figure 12.10 shows the 3 ways that muscles product ATP.

D. Muscular Disorders see definitions
1. Common muscular conditions
a. spasms, convulsions, cramps, facial tics, strain, sprain
b. tendinitis and bursitis
2. Muscular diseases
a. myalgia and fibromyalgia
b. muscular dystrophy
c. myasthenia gravis
d. amyotrophic lateral sclerosis
E. Homeostasis
1. Both systems produce movement
a. movement essential to maintaining homeostasis
b. skeletal & muscular systems work together to enable body movement
c. allow us to respond to changes in environment
d. other movements contribute to homeostasis - chewing food, contractions of peristalsis, beating of heart, movement aids in venous return
2. Both systems protecy body parts
3. Bones store and release calcium
4. Blood cells produced in bones
5. Muscles help maintain body temperature
Figure 12.12 shows how systems of the human body work together.

Definitions from Chapter 12 can be found here.

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Unit 3, Online Lab #1: Leech Neurons

2008-07-01T08:00:00.003-07:00

Screen shot of the manipulator with the oscillope trace:

Ultra-violet image of the neuron with dye in it showing it has the shape of a sensory neuron:

1. What is the electrode measuring?
The electrode is measuring voltage. When combined with the measurement of the reference electrode, you are making a measurement of the membrane potential (potential difference across the neuron's membrane).

2. Why use leeches in neurophysiology experiments?
The leech is used because it has a simple nervous sytem. Simple systems are easier to understand. What is learned from a simple system can be applied to more complex systems, because simple nervous systems obey many of the same rules as complex ones. We can use what we learn about the leech's nervous sytem to help us understand more about our own brain. Their neurons are large which make them (relatively) easy to penetrate.

3. What is the difference between a sensory and a motor neuron?
A sensory neuron transmits nerve impulses to the CNS after it's sensory receptor (exteroceptor or interoceptor) has been stimulated by either the external environment or internal enviroment. A motor neuron transmits nerve impulses away from the CNS to an effector (muscle fiber or gland).

4. Do you think a leech experiences pain? What is pain?
This was a tough question. My initial reaction is to say no. Because they are much simpler beings, it's hard to imagine that they can feel pain. I think what makes it difficult to comprehend is that humans tie emotions to pain. But when strictly looking at the definition of pain, yes, I think leeches experience pain.

Pain is a sensation that is induced by a stimulus which is derived from damaged tissue. It is characterized by physical discomfort.

5. What were the two most interesting things about doing this lab?
I liked learning about the method and equipment used to measure membrane potential of neurons. I also liked the way the listed each specific tool, what it's used for, and how much it can cost.

6. Anything you found confusing or didn't like about the lab?
Once or twice I wanted to go back to find something I had previously read and had a little difficulty finding it. Other than that I really liked this lab.

Compendium Review Unit 3 Major Topic: Nervous Function

2008-06-29T11:24:00.020-07:00

Nervous Function

I. Nervous System
II. Senses

I. Nervous System
A. Overview of the Nervous System
1. Functions: receives sensory input, CNS performs integration, CNS generates motor output
2. Nervous tissue: neurons, neuroglia
3. Neuron types and structure
a. sensory neuron, interneuron, motor neuron
b. sensory receptors, effectors
c. cell body, dendrites, axon
4. Myelin sheath
a. formed by Schwann cells in PNS
b. formed by oligodendrocytes in CNS
c. gaps in sheath - nodes of Ranvier
d. gives white, glistening appearance to nerve fibers, good insulator
5. The nerve impulse
a. resting potential - axon not conducting impulse, inside more negative, more Na+ outside, more K+ inside, membrane permeable to K+
b. sodium-potassium pump
c. action potential
i. sodium gates open - Na+ flows in - depolarization: -65mV to +40mV
ii. potassium gates open - K+ flows out - repolarization: 40mV to -65mV
iii. sodium-potassium pump restores resting potential: Na+ out, K+ in
6. Propagation of an action potential
a. each action potential generates another along the length of an axon
b. unmyelinated axon - action potential at 1 locale stimulates adjacent part, 1m/sec
c. myelinated axon - saltatory conduction - 100m/sec
d. multiple sclerosis & leukodystrophies - demyelination - slows propagation
e. all-or-none event
f. intensity of message determined by how many nerve impulses are generated w/in a given time span
g. refractory period - sodium gates cannot open, ensures action potential cannot move backward
7. The synapse
a. axon terminal ends cell body or dendrite of another neuron
b. neurotransmitters transmit impulse across synaptic cleft
i. nerve impulses reach axon terminal
ii. Ca2+ enters terminal - stimulate synaptic vesicles to merge w/sending membrane
iii. neurtransmitter molecules released to synaptic cleft & diffuse to rcving membrane, bind with specific receptor proteins
c. neurotransmitters cause excitation (sodium gates open Na+ in) or inhibition (K+ in)
d. neurotransmitters removed from cleft after initiating response - prevents continuous stimulation/inhibition
e. neurotransmitter molecules
i. ACh, NE, dopamine, serotonin, glutamate, GABA
ii. drugs affecting nervous system: act by interfering w/ or potentiating the action of neurotransmitters
f. synaptic integration - summing of excitatory & inhibitory signals
Figure 13.4 from the text details the structure and fuction of the synapse.B. The Central Nervous System
1. The spinal cord
a. structure
i. gray matter - portions of sensory & motor neurons, interneurons, dorsal root - sensory fibers entering, ventral root - motor fibers exiting
ii. white matter - ascending tracts - info to brain - mostly dorsal, descending tracts - info from brain - mostly ventral
b. functions
i. means of communication btwn brain & peripheral nerves
ii. reflex actions
Figure 13.7 shows an overview of the spinal cord.2. The brain
a. the cerebrum (lateral ventricles)
i. cerebral hemispheres
ii. cerebral cortex - primary motor & sensory areas, association areas, processing centers, central white matter
b. the diencephalon (third ventricle)
i. hypothalamus -integration - maintains homeostasis-regulates hunger, sleep, thirst body temp, water balance. controls pituitary gland
ii. thalamus - rcvs sensory input, integration - visual, auditory, somatosensory, involved w/arousal of cerebrum
iii. pineal gland - secretes melatonin
c. the cerebellum (fourth ventricle)
i. rcvs sensory input - eyes, ears, joints, muslces
ii. rcvs motor output from cerebral cortex - where parts should be
iii. integration - sends motor impulses to skeletal muscles
iv. balance and posture
d. the brain stem - relay station for tracts btwn cerebrum & spinal cord or cerebellum, reflex centers for visual, auditory, tactile responses
i. pons - bundles of axons btwn cerebellum & rest of CNS, works w/medulla oblongata - regulate breathing, has reflex centers - head movement
ii. medulla oblongata - reflex centers - heartbeat, breathing, vasocontriction, vomiting, sneezing, coughing, hiccuping, swallowing
iii. reticular formation - major component of the reticular activating system
Figure 13.10 from the text shows the primary motor and somatosensory areas of the cerebral cortex. Other important images can be found here.C. The Limbic System and Higher Mental Functions
1. The limbic system
a. "evolutionary ancient group of linked structures deep w/in the cerebrum that is a functional group rather than an anatomical one."
b. blends primitive emotions and higher mental functions
c. amygdala - cause experiences to have emtotional overtones
d. hippocampus - learning and memory
2. Higher mental functions
a. memory and learning
i. short-term (prefrontal), long-term (semantic + episodic)
ii. skill memory - involves all motor areas of cerebrum below level of consciousness
iii. long-term memories stored in sensory association areas of cerebral cortex, hippocambus - bridge btwn association areas (storage) & prefrontal area (utilization)
3. Language and speech
i. dependent on semantic memory
ii. seeing & hearing words depends on sensory centers in occipital & temporal lobes
Figure 13.12 from the text illustrates the limbic system of the brain.D. The Peripheral Nervous System
1. Somatic system
a. serve skin, skeletal muscles, tendons
b. nerves - info from external sensory receptors to CNS, motor commands from CNS to skeletal muscles
c. reflexes & the reflex arc - path of nerve impulse when you touch a pin (sensory receptor hand - sensory fibers to dorsal-root ganglia - spinal cord - interneurons - motor neurons - effector )
2. Autonomic system
a. sympathetic and parasympathetic
i. preganglionic fibers arise from middle (thoracolumbar) partion of spinal cord
ii. function automatically and involuntary
iii. innervate all interanl organs
iv. utilize 2 neurons and 1 ganglion for each impulse
b. sympathetic division (NE primary neurotransmitter)
i. preganglionic fibers short, postganglionic fibers long
ii. fight or flight - accelerates heartbeat, dialates bronchi, ihibits digestive tract
c. parasympathetic division (ACh neurotransmitter)
i. few cranial nerves and fibers arising from sacral portion of spinal cord (craniosacral portion of autonomic sys)
ii. preganglionic fibers long, postganglionic fibers short
ii. promotes all internal responses associated with a relaxed state - pupil contraction, promotes digestion, retards heartbeat
Figure 13.14 from the text provides an overview of the PNS. Table 13.1 compares the motor pathways of the somatic and autonomic systems. Click here for images from the text of the somatic system and the autonomic system.E. Drug Abuse
1. Alcohol
2. Nicotine
3. Cocaine
4. Methamphetamine
5. Heroine
6. Marijuana

Definitions from Chapter 13 can be found here.

II. Senses
A. Sensory Receptors and Sensations
1. Types of sensory receptors
a. chemoreceptors
b. photoreceptors
c. mechanoreceptors
d. thermoreceptors
2. How sensation occurs
a. sensory receptors generate nerve impulse
b. if stimulus sufficient, nerve impulse travel along sensory fiber in PNS to CNS
c. nerve impulses reach spinal cord and conveyed to brain
d. if reach cerebral cortex,sensation & perception occur
e. sensory receptors carry out integration b4 initiating nerve impulses (eg sensory adaptation)
Figure 14.1 from the text shows a general overview of sensation and perception. Table 14.1 from the text lists several sensory receptors and related information.B. Proprioceptors and Cutaneous Receptors
1. Proprioceptors
a. mechanoreceptors
b. involved in reflex actions that maintain muscle tone
c. help us know position of limbs in space by detecting degree of muscle relaxation, stretch of tendons, movement of ligaments
2. Cutaneous receptors
a. located in dermal layer of skin, make skin sensitive to touch, pressure, pain, temp
b. touch - Meissner corpuscles, Krause end bulbs, Merkel disks, root hair plexus
b. pressure - Pacinian corpuscles, Ruffini endings
c. temperature - free nerve endings in epidermis
3. Pain receptors nociceptors
a. sensitive to chemicals released by damaged tissues
b. referred pain - eg pain from heart is felt in left shoulder and arm
Figure 14.3 from the text illustrates the various sensory receptors in the skin.C. Senses of Taste and Smell
1. Sense of taste
a. taste buds - on tongue, isolated on hard palate, pharynx, epiglottis
b. how the brain receives taste information - molecules bind to receptor proteins of microvilli on taste cells - nerve impulses generated - travel to brain - interpretation in gustatory cortex
2. Sense of smell
a. olfactory cells - 10 - 20 million high in nasal cavity
b. how the brain receives odor information
i. several hundred types receptor proteins - each olfactory cell has only 1 type
ii. like olfactory cells - nerves lead to same neuron in olfactory bulb
iii. odor molecules bind to specific receptors
iv. odor's signature in olfactory bulb determined by which neurons stimulated
v. neurons communicate info via olfactory tract to olfactory area of cerebral cortex
Figures 14.4 and 14.5 from the text show the taste and smell receptors.D. Sense of Vision
1. Anatomy and physiology of the eye
a. Table 14.2
b. function of the lens
i. cornea with lens and humors - focuses images on retina
ii. viewing near object - ciliary muscle contracts - tension released on suspensory ligaments - allows lens to round up
iii. viewing far object - ciliary muscle relaxed - suspensory ligaments taut - lens is flat
c. visual pathway to the brain
i. photoreceptors - absorption of light ->rod cells - rhodopsin splits into opsin & retinal - release of inhibitory molecules cease - signals go to other neruons in retina. ->cone cells - Blue, green, red pigments
ii. retina - rod & cone cells synapse with bipolar cells - synapse with ganglion cells whose axons become the optic nerve. many (150) rods active 1 ganglion. some cones activates 1 ganglion. integration occuring as signals pass to bipolar & ganglion
iii. blind spot
iv. from the retina to teh visual cortex - impulses from eyes along optic nerve to optic chiasma. fibers from rt 1/2 of each retina converge, continue in rt optic tract. fibers from left 1/2 of each retina converge, continue in left optic tract. fibers synapse with neurons in nuclei w/in the thalamus. nerve impulses to visual cortex
2. Abnormalities of the eye near & farsightedness, astigmatism
Figure 14.6 from the text shows the anatomy of the human eye. Additional images from the text can be found here.E. Sense of Hearing
1. Anatomy and physiology of the ear
a. outer ear - pinna, auditory canal
b. middle ear - tympanic membrane, oval & round window, ossicles (malleus, incus, stapes)
c. auditory tube
d. inner ear - semicircular canals & vestibules (equilibrium) & cochlea (hearing)
e. auditory pathway to the brain - tympanic memb. vibrates - to malleus, incus stapes (pressure multiplied x20). stapes strikes oval window - pressure to fluid in cochlea. movement of pressure waves from vetibular to tympanic canal across basilar membrane causes stereocilia of hair cells to bend. nerve impulses begin in cochlear nerve, travel to auditory cortext in temporal lobe for interpretation
Figures 14.13 and 14.14 illustrate the general anatomy of the ear and, more specifically, of the inner ear.F. Sense of Equilibrium
1. Rotational equilibrium pathway
a. mechanoreceptors in semicircular canals detect rotational equilibrium
b. displacement of cupula in ampulla causes stereocilia of hair cells to bend
c. pattern of impulses to brain changes
d. brain uses info to adjust motor output to right position in space
2. Gravitational equilibrium pathway
a. mechanoreceptors in utricle (back-forth movement) & saccule (up-down movement) detect movement of head in vert or horiz plane
b. movement causes displacement of otoliths, otolithic membrane sags, stereocilia of hair cells bend.
Click here for figure 14.15 from the text which shows the mechanoreceptors for equilibrium.

Definitions from Chapter 14 can be found here.

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Unit 2 Evaluation

2008-06-27T12:57:00.003-07:00

1. What were the three aspects of the assignments I've submitted that I am most proud of?

- The amount of time I spent on the compendiums.
- I like my tables in the lab project.
- Acknowledging that I need to make some changes in my life.

2. What two aspects of my submitted assignments do I believe could have used some improvement?

- I need to spend a little less time on the online labs, and devote more time to the ethical issue.

- I think the conclusion to my lab project could have been better.

3. What do I believe my overall grade should be for this unit?
A

4. How could I perform better in the next unit?
Start the ethical essay and the lab project right away.

Unit 2 Ethical Essay: Food

2008-06-27T11:19:00.003-07:00

When I was growing up in my parents house with my 3 sisters, dinner time was an event. It was a group affair. Mom would start dinner. She stayed at home while my dad worked on the farm all day. She made everything from scratch. The four of us would trickle in to help set up the table.

She would yell at us for snacking out of the salad bowl before dinner started. I distincly remember getting my hand slapped for that on more than one occasion. That was and still is one of her biggest pet peeves. Every night we would sit down to the best dinner one of the smallest kitchens (sans T.V.) in existance. We would eat and talk and tease each other.

Occasionally, the teasing would lead into a small food fight. Yes, I am embarrassed to say that I may have missed one of my sisters now and then and regrettably ended up whipping jello on the wall of my parents kitchen. Laughter would erupt; we would get into trouble. We would have to clean the whole kitchen including the walls, by ourselves.

Fast-forward 20 years. My husband and I both work. We both love mountain biking...for the workout, the freedom, the time spent in nature, the smell of the pines, the feel of the air, for the rush. It is a blast. We both feel so lucky to have a hobby that we both love. We can do it together and it is good for us. It gets us outside.

The downside to having jobs and having a hobby that we both like and can spend an endless amount of time doing, is that our time around the dinner table suffers. We tend to make a large portion of something once or twice a week and eat the leftovers for a few days. The good thing is that we love Mexican food. We have probably eaten burritos for dinner 80% of the time over the last year. We are using fairly heathly ingredients (chicken, blackbeans, corn, cilantro, tomatoes, cheese, potatoes), but some of them come from a can instead of being fresh. We also love to have salad every night.

Regardless of what we eat for dinner, we do not spend the time at the dinner table like I did when I was little. It feels like we get home and race through dinner so we can sit down and relax. We need to change our mind set so that we incorporate relaxation into our meal instead of hurrying through it.

I also love the idea of buying locally and eventually growing some of my own produce. I need to figure out how to make that a part of my life. The websites from the link for this essay are a great way to get started.

Unit 2 Lab Project: Exercise Physiology

2008-06-27T06:03:00.010-07:00

note: click on any image to view full size

INTRODUCTION
Delivery of oxygen: Possibly the single most important function of the blood that runs through our vessels. We breath air in, the blood in our lungs picks up the oxygen, and after a quick run back through the heart, that oxygenated blood is pumped out to the tissues of the body. The oxygen we breath allows our cells to carry on the never ending cycle of work that they do to keep us alive. Oxygen is part of the final step cellular respiration, the process by which our mitochondria produce ATP, the energy currency of our cells.

The purpose of this lab was to understand the impact that different activities have on basic metabolic rates. Different activities require more or less from our cells. More strenuous activities require more energy; more energy produciton requires more oxygen. The rates we were to measure were pulse, respirations, and systolic and diastolic blood pressures. We were to select 3 different activities to perform. After completing each activity, we were to measure the 4 metabolic rates and compare the mean of each to the mean of our baseline rates.

HYPOTHESIS
HOW DO I THINK MY METABOLIC RATES WILL COMPARE TO BASELINE AFTER....?
My hypotheses are listed in the table below.

MATERIALS AND METHODS
I borrowed a Mabis SmartRead blood pressure monitor from my aunt. This piece of equipment measured systolic blood pressure, diastolic blood pressure, and pulse. The photo below shows the monitor with the cuff wrapped around my bicep. Once the cuff is wrapped tightly around the bicep, there is a blue button that you push. The monitor fulls the cuff with air, slowly releases the air, and provides the readings in the digital display.

To measure my respirations per minute, I used my wristwatch that has a second hand. As the blood pressure monitor was taking my other metabolic measurements, I would keep an eye on my wristwatch and count the number of respirations in 30 seconds. I then took that number and multiplied by 2 to determine the number of respirations per minute.

The first activity I chose was eating. The picture below is of me and my dad getting ready to eat breakfast.

The second activity I chose was a 1 mile time trial on my bike. The picture below is of me riding after I completed the second repetition.

The third activity I chose was a brisk walk around the block. The picture below is of me walking after I completed my first repetition.

DATA
The table below shows the raw data. Included are all four metabolic rates at baseline (5 reps) and after each of the 3 activities (4 reps). Also included is the mean for each.

GRAPH: Mean pulse - baseline and 3 activities

GRAPH: Mean respirations - baseline and 3 activities

GRAPH: Mean systolic blood pressure - baseline and 3 activities

GRAPH: Mean diastolic blood pressure - baseline and 3 activities

ANALYSIS OF DATA
Where my predictions correct?

In the discussion below, when I refer to any of the metabolic rates, I am referring to the mean.

I hypothesized that my pulse would go up as compared to my baseline after each of the 3 activities (eating, biking, walking). I was incorrect when I hypothesized that my pulse would go up after eating. In fact, my baseline pulse and my pulse after eating were the same. My hypotheses about my pulse going up after biking and after walking were both correct.

For respiration rate, I predicted that it would stay the same after eating and go up after biking and after walking. All 3 predictions were correct.

I hypothesized that for systolic blood pressure, each of the 3 activities would cause it to go up. My hypothesis for eating was incorrect. In fact, my baseline and after eating systolic blood pressure were the same. My hypotheses for biking and walking were both correct.

For diastolic blood pressure, I predicted that it would go down after eating and go up after biking and walking. All three of these predictions were correct.

PROBLEMS WITH DATA OR TECHNIQUE
I did encounter a few issues during this experiment.
1. Error message on blood pressure machine - After completing the second repetition of my walk, I tried to measure my blood pressure the monitor gave me an error message. I had to take a second reading which allowed all of my metabolic rates to decrease towards baseline.
2. Time lapse - After my first bike ride, I had to walk into the house to take all 4measurements. Again, this delay allowed my body time to recover. After this I left all necessary equipment in the garage for quick use after biking or walking.
3. Time of day - I took baseline measurements at different times of the day, because I figured my activities would be performed at different times of the day. Ideally, measurements for baseline and all activities would be performed at the same time every day, as baseline metabolic rates vary throughout the day (ie - pulse and blood pressure is lowest in the morning).
4. Measuring respirations - It is very difficult to take this measurement on your own. As soon as you concentrate on counting the number of respirations, you are aware of your breathing rhythm. It is very easy to voluntarily control this rate without meaning to.

CONCLUSION
In general, physical activities are going to increase metabolic rates. These activities consume energy more quickly than sedentary activities do. In response, your body needs to get more oxygen to its cells more quickly. You start breathing harder/faster(respirations) and your heart starts pumping faster (pulse) to move the oxygenated blood to your tissues faster. The faster rate of blood flow causes your blood pressure to rise.

Unit 2, Online Lab #2: A Day of Food

2008-06-25T16:02:00.004-07:00

My screen shot from the Balance Mind, Body and Soul website.

-How healthy a daily diet do you think this is? Why?
I think this is a fairly healthy diet. It's pretty well-rounded...fruit, vegetables, whole grains, poultry, dairy. It does not include too much processed food.

-What would you change about this day's eating, if anything?
I did not like the sodium intake at all! The saturated fat is higher than I expected as well. This day was somewhat unusual in that I had lunch meat, which I do not normally have. Pasta is not an unusual meal for me, but pasta with sausage is. Those two items really up'd the sodium. Bottom line, I would like to see much lower sodium and saturated fat intake.

-Do you find this kind of nutritional tracking helpful? Why or why not?
I think it's great. In general, I think I have pretty healthy eating habits, but this kind of site lets you know exactly where you stand. What I don't like about this particular site is that (I'm assuming) the nutrition information is based on Sodexo's recipes. I very rarely add salt when I cook. I am assuming again that Sodexo probably prepares their dishes with more salt than I use. This exercise had definitely peaked my interest in nutritional tracking. I would like to use a site that allows me more control of all the ingredients....but at the same time that seems a bit overwhelming! And it might also defeat the purpose. I think the intention here is to give a person a general idea of what kind of diet he or she she has, not to get bogged down with the minutia.

Compendium Review Unit 2 Major Topic: Nutrition

2008-06-24T08:41:00.011-07:00

Nutrition

Table of Contents
I. Digestive System and Nutrition
II. Converting Food into Energy

I. Digestive System and Nutrition
A. Overview of Digestion
1. Ingestion, digestion, movement, absorption, elimination
2. Wall of the digestive tract
a. mucosa (mucous membrane) - lines tract, protects wall from enzymes, contains glands in mouth, stomach, & small intestine, diverticulitis (pouches in mucosa)
b. submucosa - broad band of connective tissue, contains blood & lymphatic vessels & nerves, inflammatory bowel disease (colitis, inflammatory response)
c. muscularis - 2 layers of smooth muscle (circular & longitudinal), moves GI contents, irritable bowel syndrome (spastic colon, contractions of wall)
d. serosa (serous membrane) - secret serous fluid, part of peritoneum, appendicitis can lead to peritonitis
Figure 8.1 from the text shows an overview of the human GI tractB. First Part of the Digestive Tract
1. The mouth
a. mechanical (teeth and tongue) and chemical (saliva)
2. The pharynx and esophagus
a. swallowing - voluntary and involuntary (once food pushed back into pharynx)
b. peristalsis - rhythmic contraction that pushes food along esophagus
Figure 8.4 from the text shows the path of a bolus as it moves through the first part of the GI tract.C. The Stomach and Small Intestine
1. The stomach
a. continuous with esophagus and duadenum of small intestine
b. stores food, initiates digestion of protein, controls movement of chyme
c. muscularis contains 3 layers of smooth muscle - circular, longitudinal, oblique
d. mucosa has rugae & gastric pits -> gastric glands -> gastric juice (pepsin,HCl, mucus)
2. The small intestine
a. 18ft long
b. digestion completed here
c. duodenum receives enzymes from pancreas and bile from liver and gallbladder
d. nutrients (sugars, amino acids, fatty acids, glycerol) absorbed by sm intestine
e. villi and microvilli increase surface area for absorption
3. Lactose intolerance sufferers lack enzyme, lactase
4. Obesity: diabetes type 2 and cardiovascular disease
a. cells become resistant to insulin and can't utilize glucose
Figure 8.5 from the text illustrates the structure and function of the stomach, table 8.1 which lists the major digestive enzymes, and figure 8.6 which depidcts the anatomy of the small intestine can be found here for later reference. Figure 8.7 which shows digestion and aborption of nutrients is shown below.D. Three Accessory Organs and Regulation of Secretions
1. Three accessory organs
a. pancreas - produces pancreatic juice into duodenum, secrets insulin into blood
b. liver - cleanses blood, stores iron & vitamins, stores glucose, breaks down glycogen, converts glycerol & amino acids to glucose, urea is byproduct, makes plasma proteins
c. gallbladder - stores bile
d. liver disorders - hepatitis, cirrhosis,
2. Regulation of digestive secretions
a. controlled by nervous system and by digestive hormones
Figure 8.8 from the text illustrates the three accessory organs.E. The Large Intestine and Defecation
1. Functions of the large intestine
a. absorbs water
b. intestinal flora produce vitamins which are absorbed by the large intestine
c. forms feces
d. defecation
2. Disorders of the colon and rectum
a. diarrhea, constipation, hemorrhoids, diverticulosis, IBS, IBD, polyps, cancer
Figure 8.10 from the text shows the anatomy of the large intestine.F. Nutrition and Weight Control
1. How obesity is defined
a. body mass index - looks at height and weight
2. Classes of nutrients
a. carbohydrates - simple (eg glucose) complex (body breaks down to glucose)
b. complex carbohydrates better than refined grains
c. proteins - digested to amino acids
d. 8 essential amino acids - daily supply needed
e. lipids - best sources - oils
f. polyunsaturated (contain essential fatty acids)- corn and safflower
g. monounsaturated - olive and canola
3. Minerals
a. trace - body contains less than 5 grams, major - body contains more than 5 grams
b. calcium - construct bones & teeth, nerve conduction, muscle contraction
c. sodium - regulates body's water balance
4. Vitamins
a. 13 vitamins - 4 fat-soluble, 9 water-soluble
b. some are portions of enzymes, others precursors
c. antioxidants - vit. C, E, & A believed to defend the body against free radicals
d. vitamin D - after modification in kidneys & liver, promotes the absorption of calcium by the intestines
5. How to plan nutritious meals
a. eat a variety of foods
b. eat more fruits and vegetables
c. eat less food with saturated or trans fat, sugar, cholesterol, salt, alcohol
d. exercise
e. eat less processed foods
6. Eating disorders
a. anorexia nervosa, bulimia nervosa, binge-eating disorder, muscle dysmorphia
II. Converting Food into Energy
A. Glycolysis1. Glucose converted to pyruvate
2. NET result of single glycolysis run 2 NADH, 2 ATP
3. Lactic acid is end end product under anaerobic conditions
4. 6-Carbon sugar diphospate split into 2 3-Carbon sugar phospate molecules
5. Aerobic conditions, pyruvate is further oxidized to yield more ATP
B. Krebs Cycle1. Occurs in mitochondrion
2. Acetyl-CoA from pyruvate enters Krebs Cycle
3. Single turn of cycle yields 1 ATP, 3 NADH, 1 FADH2
4. Initial reaction involves addition of a 2-Carbon to a 4-Carbon molecule
C. Electron transport chain
1. Electrons are accepted in the following order: cytochrome c, cytochrome c oxidase, oxygen
2. Electrons transferred through the chain originally belonged to NADH and FADH2
3. Movement of protons through ATP synthase: from intermembrane space into matrix
4. Water is produced when oxygent accepts electrons
5. Oxidative phosphorylation is the production of ATP from ADP plus phosphate. The energy used is derived from the movement of proton from the intermembrane space to the matrix
D. How NAD+ Works
1. Cells obtain energy by oxidizing food molecules
2. Coenzyme NAD is reduced NAD+ + H -> NADH
3. Hydrogen atom consists of a proton and an electron
4. Reduction is the addition of an electron, oxidation is the removal of an electron
5. When one molecule is reduced another must be oxidized
6. NADH serves as an electron carrier that can donate its hydrogen

Definitions for chapter 8 can be found here.
REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Unit 2, Online Lab #1: Blood Pressure

2008-06-18T09:28:00.005-07:00

I was having difficulty emailing and/or copying from the Virtual Lab website, so I decided to create my own graph using the Create a Graph website you recommended. I also typed the journal questions and answers directly into my blog instead of using their journal because of the same issues. I have included screen shots from the Virtual Lab website to show that my work was performed there.

JOURNAL ENTRIES (pre-lab):
Question 1: State a problem about the relationship of age and gender to blood pressure.
Answer 1: Although age and gender impact blood pressure, there are other factors that impact it as well. Genentics and overall health also play a role in determining blood pressure.
Question 2: Use your knowledge about the heart and the circulatory system to make a hypothesis about how the average blood pressure for a group of people would be affected by manipulating the age and gender of the group members.
Answer 2: As age increases, average blood pressure will increase (for both men and women). Men will have higher blood pressure than women.
Question 3: How will you use the investigation screen to test your hypothesis? What steps will you follow? What data will you record?
Answer 3: I will measure the blood pressure of a group of women and a group of men for each age group.

I will start with the youngest age group and measure a group of women. I will stay with the same age group and measure a group of men. I will move on to the next age group and repeat the process until I have gone through each age group. After the measurement is done for each age group/gender combination, I will record the measurements in the table.

After the measurements are complete for each group, I will also review the medical charts and note hereditary history and unhealthy habits that may impact blood pressure.

DATA TABLE AND GRAPH:
The data table is shown in the following two screen shots.

I graphed the data using the Create a Graph website. The first graph shown below is the one from that website. The second graph is a screen shot of the graph generated in the Virtual Lab website. I was not happy with this graph. It was difficult to see the entire graph in one screen shot and the axes were labeled incorrectly.

JOURNAL ENTRIES (post-lab):
Question 4: Analyze the result of your experiment. Explain any patterns you observed.
Answer 4:

Over the age of 17 and on average, men have higher blood pressure compared to women of the same age group
On average, females in the 18-24 age group have lower blood pressure compared to females in the 11-17 age group
On average, females in the 25-34 age group have lower systolic blood pressure compared to females in the 11-17 age group. The average diastolic blood pressure of the same two age groups is the same.
On average, the blood pressure of males increases as you move up from one age group to the next.
Taking both systolic and diastolic blood pressure into account, the smallest change from one age group to the next is from the 18-24 age group to the 25-34 age group. This is true for men and women.
The other contributing factors (weight, family history, salt in diet, exercise, and alcohol consumption) did not seem to have much of an impact on the blood pressure of those in the 25-34 age group. In other words, those in this age group could get away with being a few pounds overweight and/or eating a high salt diet without it negatively impacting their chances of having hypertension.
The other contributing fators had a much greater impact for those over 35.
Being overweight only did not necessarily mean one will have hypertension.
When combined with one of the other factors, being overweight greatly increased the chances of having hypertension.
There was not one of the other contributing factors was seen in every person with hypertension.

Question 5: Did the result of your experiment support your hypothesis? Why or why not? Based on your experiment what conclusion can you draw about the relationship of age and gender to group blood pressure averages?
Answer 5: The results of my experiment supported part of my hypothesis to a certain extent. I was correct that men would have higher blood pressure compared to women. I was partially correct when I said that as age increased, so would blood pressure. This was not true when comparing the average blood pressure of those in age group 11-17 to the average blood pressure of those in age group 18-24. Both the average systolic and diastolic blood pressure in the 18-24 year olds was lower than that of the 11-17 year olds. The conclusion that I draw is that in general, as you (male or female) get older, your blood pressure is going to increase. And men are going to have higher blood pressure compared to women of the same age.
Question 6: During the course of your experiment, did you obtain any blood pressure reading that were outside of the normal range for the group being tested? What did you notice on the medical charts for these individuals that might explain their high reading?
Answer 6: Yes, I did obtain blood pressure readings that were outside the normal ranges. I noticed that the high blood pressure could be explained by one of the other contributing factors. For example, most of those with high blood pressure were overweight, from just a few pounds up to almost 50 pounds overweight. I also noticed that most of those with high blood pressure also had one or more of the other contributing factors to blame for it. Some of them also had a diet high in salt, others did not exercise, while others consumed alcohol or had a family history of hypertension. There was only one person who was under weight that had high blood pressure. The only contributing factor that person was guilty of was eating a high salt diet. That person was also male.
Question 7: List risk factors associated with the hypertension. Based on your observation, which risk factor do you think is most closely associated with hypertension?
Answer 7: Risk factors associated with hypertension are as follows:

Obesity
Family history of hypertension
High salt diet
Lack of exercise
Alcohol consumption

I think being overweight is most closely associated with hypertension.
Question 8: What effect might obesity have on blood pressure? Does obesity alone cause a person to be at risk for high blood pressure? What other factors, in combination with obesity, might increase a person's risk for high blood pressure?
Answer 8: Obesity has many negative health implications. But if you think about just the extra weight an obese person has to carry around....Their heart needs to pump enough blood to supply oxygen and nutrients to that extra weight. The additional blood flow required may increase blood pressure. All of the other factors (listed above) in combination with obesity might contribute to high blood pressure. A few other factors not listed are tobacco use and stress.

Compendium Review Unit 2 Major Topic: Oxygen/Microbes/Immunity

2008-06-17T05:42:00.039-07:00

Oxygen...Microbes...Immunity

Table of Contents
I. Cardiovascular System: Heart and Blood Vessels
II. Cardiovascular System: Blood
III. Lymphatic System and Immunity
IV. AIDS Supplement
V. Sickle Cell Anemia

I. Cardiovascular System: Heart & Blood Vessels
A. Overview of the Cardiovascular System (heart & blood vessels)
1. Circulation performs exchanges
a. circulation of blood - to service cells
b. blood removes waste product from tissue fluid
c. blood delivers oxygen and nutrients to tissue fluid
d. lungs - exchange carbon dioxide for oxygen
e. kidneys - remove waste
f. intestines - where nutrients enter the blood
g. liver - removes poisons, takes up amino acids and returns proteins
2. Functions of the cardiovascular system
a. heart contracts -> blood pressure -> moves blood
b. blood vessels transport - heart, arteries, capillaries, veins, heart
c. capillaries exchange
d. blood flow regulated by heart and blood vessels
3. Lymphatic system
a. collects excess tissue fluid
Figure 5.1 from the text shows a general view of how the cardiovascular system works with the other systems of the body for the exchange of O2, CO2, waste, and nutrients.

B. The Types of Blood Vessels(artery, arteriole, capillary, venule, vein)
1. Arteries: from the heart (endothelium, smooth muscle & elastic tissue, connective tissue)
2. Capillaries: exchange (endothelium, basement membrane)
a. bypassed by arteriovenous shunt
3. Veins: to the heart (less smooth muscle, less connective tissue, thinner)
a. valves - in veins carrying blood against force of gravity
Figure 5.2 from the text shows an overview of the tissues and vessels that make up and surround a capillary bed.C. The Heart is a Double Pump
1. Passage of blood through the heart
a. O2 POOR blood -> sup vena cava and inf vena cava -> right atrium
b. right atrium -> tricuspid valve -> right ventricle
c. right ventricle -> pulmonary semilunar valve -> pulmonary trunk -> 2 pulmonary arteries -> lungs
d. pulmonary veins with O2 RICH blood -> left atrium
e. left atrium -> bicuspid valve -> left ventricle
f. left ventricle -> aortic semilunar valve -> aorta -> body proper
g. atria - thin walled, ventricles - thicker walled (pump blood farther)
2. Heartbeat is controlled
a. internal control of the heartbeat - SA node-atrium->AV node->AV bundle->Purkinje fibers-ventricles
b. external control of heartbeat - medulla oblongata, epinephrine and norepinephrine
3. Electrocardiogram is a record of the heartbeat (PQRST waves)
Figure 5.3 from the text illustrates the external anatomy of the heart. Figure 5.4 from the text illustrates a cross sectional view of the anatomy of the heart.
D. Features of the Cardiovascular System
1. Pulse rate equals heart rate (arterial walls pulse when left ventricle contracts
2. Blood flow is regulated
a. blood pressure moves blood in arteries
b. blood flow - slow in capillaries
c. blood flow in veins returns blood to heart (blood pressure low, velocity high=skeletal muscle pump, respiratory pump, valves)
d. blood pressure dependent on: volume of space involved, # of molecules in space, kinetic engergy of molecules
E. Two Cardiovascular Pathways
1. Pulmonary circuit: exchange of gases
a. CO2 given off and O2 taken into blood at pulmonary capillaries
2. Systemic circuit: exchanges with tissue fluid
a. tracing the path of blood (aorta, proper branch of aorta, region, returning vein, vena cava)
b. coronary circulation - supplies the heart
c. hepatic portal system - connects digestive tract to liver and liver to inf vena cava
Figure 5.10 from the text shows the flow of blood through the pulmonary and systemic circuits. Figure 5.11 from the text shows the systemic circuit and its major arteries and veins.F. Exchange at the Capillaries
1. Blood pressure and osmotic pressure control movement of fluid through capillary wall
2. Arterial end of cap. bed - blood pressure higher, water out
3. Capillary bed - pressures equal, solutes diffues (CO2, wastes in & O2, nutrients out)
4. Venule end of cap. bed - osmotic pressure higher, water in
5. Excess fluid collected by lymphatic capillaries
Figure 5.12 shows the exchanges that take place at the capillariesG. Cardiovascular Disorders
1. Disorders of the blood vessels
a. hypertension - high blood pressure (atherosclerosis, plaque, thrombus, embolus)
b. stroke, heart attack, aneurysm
c. dissolving blood clots (t-PA, aspirin)
d. treating clogged arteries (bypass surgery, stent, gene therapy)
2. Disorders of the heart
a. heart transplants (left ventricle assist device, total artificial heart)

Definitions from Chapter 5 can be found here.

II. Cardiovascular System: Blood
A. Blood: An Overview
1. Functions of the blood
a. transport - O2, nutrients, CO2, waste, hormones
b. defense - phagocytosis, antibodies, blood clotting
c. regulation - picks up & transports heat, regulates pH, maintains water-salt balance
2. Composition of blood
a. formed elements - red and white blood cells and platelets, produced in red bone marrow
b. plasma
i. water
ii. salts - buffer
iii. organic molecules - glucose, amino acids, urea, plasma proteins
Below is an image take from this website that shows all of the formed elements of blood.B. Red Blood Cells & Transport of Oxygen
1. How red blood cells carry oxygen
a. hemoglobin - globin=proteing containing 4 highly folded polypeptide chains, heme=iron-containing group in center of polypeptide chain
b. iron accepts O2 in lungs, lets go in tissues
c. 1 RBC (has no nucleus) = 280 million hemoglobin molecules, 1 hemoglobin=4 O2
d. RBCs - biconcave shape=greater surface area for diffusion, internal space=O2 transport
2. How red blood cells help transport carbon dioxide
a. 7% dissolved in plasma
b. 25% combines with terminal amino groups of globin molecules of hemoglobin
c. 68% transported as bicarbonate ion in plasma
e. RBCs - lack most organelles, produce ATP anaerobically, no consumption of O2 they carry
3. Red blood cells are produced in bone marrow
a. RBC stem cell divides -> new cells differentiate into mature RBCs
b. constant regeneration - RBCs only live 120 days
c. RBCs destroyed in liver and spleen by macrophages
d. globin -> amino acids, iron -> marrow, remaining heme portion degraded
e. erythropoietin - produced in kidneys, liver, other tissue - stimulates RBC production in stem cells of bone marrow
f. blood doping
4. Disorders involving red blood cells
a. anemia - too few RBCs or low hemoglobin, due to low iron, vit B12, folic acid
b. hemolysis - rupturing of RBCs, sickle-cell disease
Figure 6.3 from the text shows the single file lines of RBCs moving through capillaries, a close up of RBCs, and the four highly folded polypeptide chains of a hemoglobin molecule.C. White Blood Cells & Defense Against Disease
1. Types of white blood cells
a. neutrophil (granular leukocyte) - 1st responders to bacterial infection
b. eosinophil (granular leukocyte) - increase in # during parasitic worm infection or allergic reaction
c. basophil (granular leukocyte) - release histamine during allergic reaction
d. mast cell (granular leukocyte - release histamine during allergic reaction
e. lymphocyte (agranular leukocyte) - T cells and B cells
f. monocyte (agranular leukocyte) - differentiate into macrophages & dendritic cells
2. Disorders involving white blood cells
a. severe combined immunodeficiency disease
b. leukemia
c. infectious mononucleosis
The image below taken from this website is of a white blood cell that is trapping bacterial cells.D. Platelets & Blood Clotting
1. Blood clotting
a. 12 clotting factors plus Ca2+
b. prothrombin activator+prothrombin+Ca2+->thrombin+fibrinogen+Ca2+->fibrin threads
2. Disorders related to blood clotting
a. thrombocytopenia - insufficient number of platelets
b. thromboembolism - dilodged thrombus obstructs blood vessel
c. hemophilia - inherited clotting disorder, deficiency of clotting factor
Figure 6.8 from the text shows the process of clotting, generalized.E. Blood Typing & Transfusions
1. ABO groups
a. type A blood - type A antigen (on surface of RBC) & anti-B antibodies (in plasma)
b. type B blood - type B antigen & anti-A antibodies
c. type AB blood - type A & type B antigens, no antibodies
e. type O blood - no antigens, anti-A & anti-B antibodies
2. Rh blood groups
a. indicates whether person has Rh factor on RBC
b. Rh- individuals do not have antibody to Rh factor, produce them if exposed
Figure 6.9 from the text illustrates the 4 ABO blood groups and associated antigens and antibodies.F. Homeostasis
Figure 6.13 is a great overview of the contribution that each of the body systems makes to the maintenance of homeostasis.

Definitions from Chapter 6 can be found here.

III. Lymphatic System & Immunity
A. Microbes, Pathogens, & You
1. Bacteria
a. single celled prokaryote, no nucleus
b. shapes=bacillus (rod), spirillum (curved), coccus (spherical)
c. anatomy=fimbriae, flagellum, capsule, cell wall, plasma membrane, piluls, plasmid, ribosome, nucleoid
d. examples of infections - strep throat, TB, botulism, food poisoning, gangrene 2. Viruses
a. bridge gap between living and nonliving
b. acellular
c. obligate parasites
d. outer capsid made of protein, inner core made of nucleic acid
e. adheres to a receptor on cell surface, injects nucleic acid
f. uses cells host's enzymes and ribosomes for replication
g. viral genetic material is DNA or RNA
h. examples of infections - colds, flu, measles, chicken pox, polio, rabies, AIDS
i. emerging viruses - transported to new location, change in vector, change in face
3. Prions
a. proteinaceous infectious particles
b. cause a group of degenerative diseases of the nervous system (CJD, mad cow, scrapie)
Figure 7.1 from the text shows the parts of a bacterium. Figure 7.4 from the text shows the parts of a virus.
B. The Lymphatic System
1. Lymphatic vessels
a. capillaries, vessels, ducts -> cardiovascular veins in shoulders
b. capillaries take up excess tissue fluid
c. thoracic duct and right lymphatic duct
d. vessels - have valves and movement of lymph dependent on muscle contraction
2. Lymphatic organs
a. red bone marrow (makes RBCs, WBCs), thymus gland(makes hormones,maturation of T cells) - both primary
b. lymph nodes (filter lymph), spleen (filters blood), lympatic nodules, Peyer's patches- secondary
C. Nonspecific Defenses
1. Barriers to entry 1st line of defense
a. skin and mucous membranes
b. chemical barriers - skin oil, persperation, tears, saliva, acidic - stomach, vagina
c. resident bacteria - normal flora
2. Inflammatory response 2nd line of defense
a. redness, heat, swelling, pain
b. WBCs rush in - neutrophils, cytokines, monocytes (macrophages), lymphocytes
d. protective proteins - complement proteins - interferons, membrane attack complex
Figure 7.9 from the text depicts the inflammatory response. Figure 7.10 from the text illustrates how protective proteins (complement system) work against a bacterium.D. Specific Defenses
1. How specific defenses work
a. respond to antigens
b. primarily responsible - lymphocytes (T cell & B cell)
c. antibody-mediated immunity - B lymphocytes contain antigen specific receptors
d. antigen fits to BCR, B cell undergoes clonal expansion
e. cloned B cells become plasma cells (produce & secrete antibody) membory cells (can fight same antigen later on)
f. structure of antibody - Y-shaped, 5 classes determined by Y structure, variable region form antigen-bodning site
g. cell-mediated immunity - T lymphocytes, TCR requires antigen-presenting cell (APC) which already phagocytized a pathogen & presents antigen to TCR on self protein
h. T cell compares antigen to self protein and activation occurs, clonal expansion
i. cytotoxic T cells (cause apoptosis in virus-infected or tumor cell) & helper T cells (regulate immunity by secreting cytokines) produced
Tables and images from the text have been uploaded for later reference here. Figure 7.12 from the text shows the structure of an antibody. E. Acquired Immunity
1. Active immunity
a. vaccines - non-virulent pathogen or it's product
b. vaccine exposure->initially no antibody->antibody increases->levels off->declines
c. booster - second exposure to increase - titer increase to greater level
2. Passive immunity
a. prepared antibodies or immune cells given to combat a disease
b. example - newborn infants (antibodies from mother thru placenta, breast milk)
c. monoclonal antibodies - detect pregnancy, ID infections, deliver toxic drugs to tumors
d. cytokines & immunity - interferons & interleukins being investigated to use as adjuncts for vaccines and for cancer treatment
Figure 7.17 from the text illustrates the production of monoclonal antibodies.F. Hypersensitivity Reactions
1. Allergies
a. immediate allergic response (caused by IgE antibodies) eg - anaphylactic shock
b. delayed allergic response (initiated by memory T cells) - eg - TB skin test, contact dermititis (poison ivy)
2. Tissue rejection
a. prevention - immunosuppressive durgs, xenotransplantation, lab organs
3. Disorders of the immune system
a. autoimmune diseases - myasthenia gravis, multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis

Definitions from Chapter 7 can be found here.

IV. AIDS Supplement
A. Origin of & Prevalence of HIV
1. AIDS caused by HIV which infects & destroys cells (helper T & macrophages) of immune systems
2. Originated in Africa
3. Prevalence of HIV
a. of the 38.6 million people infected with HIV, 24.5 million in Sub-Saharan Africa, 8.3 million in Asia, 2 million in North America, Wester and Central Europe,1.6 million in Latin America
B. Phases of an HIV Infection
1. Category A: Acute Phase
a. no apparent symptoms
b. highly infectious
c. CD4 T cell count - has never fallen below 500 cells per mm3 of blood
d. at first, antibodies low count so not detectable
e. after time, body starts producing CD4 T cells like crazy to overcome the destruction of them by HIV
2. Category B: Chronic Phase
a. CD4 count - 499 to 200 cells/mm3
b. symptoms related to poor immune system - yeast infections, cervical displasia, prolonged diarrhea, thick sores on tongue, shingles, fevers, fatigue, cough
c. HIV particles - # is increasing
3. Category C: AIDS
a. diagnosed with AIDS
b. CD4 count below 200
c. 1 or more - 25 AIDS defining illnesses (opportunistic infections)
d. death results from: Pneumocystis jiroveci pneumonia, Mycobacterium tuberculosis, toxoplasmic encephalitis, Kaposi's sarcoma, invasive cervical cancer
C. HIV Structure and Life Cycle
1. Structure
a. 2 single strands of RNA (retrovirus)
b. various proteins
c. envelope - contains embedded spikes - Gp120
d. protection: 3 protein coats (nucleocapsid, capsid, matrix)
e. matrix contains 3 enzymes: reverse transcriptase (catalyst for reverse transcription), integrase (catalyst for integration of viral DNA into DNA of host), protease (catalyst for breakdown of newly synthesized viral polypept. into viral proteins)
Taken from this website, the drawing below shows the structure of the HIV virus..2. HIV life cycle
a. attachment - HIV to plasma membrane of target cell
b. fusion - of HIV to plasm membrane
c. entry - uncoating of capsid and protein coats, RNA, viral proteins released
d. reverse transcription - reverse transcriptase - single stranded RNA -> DNA
e. integration - viral DNA and integrase into nucleus of host cell, host cell DNA spliced, and viral DNA integrated (HIV now called provirus)
f. biosynthesis and cleavage - production of more viral RNA, protease cleavs long viral polypeptide chains
g. assembly - of viral enzymes, capsid proteins, and RNA into viral particles
h. budding - virus gets envelope
3. Transmission and Prevention of HIV
a. transmitted through bodily fluids during sexual contact, needle-sharing, transfusions, birth or breast feeding
b. prevention - abstinence, sex with 1 uninfected partner, use of condom
4. HIV testing and treatment for HIV
a. tests for HIV antibody
b. treatment - available but not without concerns (drug-resistant viruses)
c. drug therapy -HAART - different drugs interfere with life cycle of HIV
d. vacccines - being studied
The image below, taken from this website, shows the life cycle of the HIV virus.V. Sickle Cell Anemia
A. Discovery and Biological Basis
1. Discovered by cardiologist James B. Herrick and his intern Ernest E. Irons
2. Patient's physical symptoms: pain in back, muslces of back, arms, dark urine, fever, weakness, dizziness, shortness of breath
3. Patient's blood test: nucleated and sickle shaped RBCs
4. Biology of RBCs
a. RBCs made up mostly of hemoglobin (Hb)
b. Hb made up of 4 protein subunit with iron atom at center of each
c. each iron atom has affinity for O2
d. Hbs most important characteristic: reversibly bind and release O2 equally
e. Hb binds O2 when oxygen pressure is high and releases it when its pressure is low
f. anemia - signifant decrease in amount of functional Hb
g. sickle cell anemia causes depletion
i. O2 carrying capactiy reduced b/c of molecular changes in sickeled cell
ii. peculiar shape and rigidity, stick together and clog small arteries
h. effects
i. short term: poor O2 delivery causes shortness of breath
ii. long term: oxygen deprivation leads to poor tissue development
iii. hemolysis & clogging of arteries and capillaries in lungs, kidneys, & liver causes system malfuction and death usually by 30
5. Genetic basis of sickle cell anemia
a. 2 forms: sickle cell anemia (more severe) and sickle cell disease (rarely show complications) discovered
b. sickle cell disease - threshold effect, where a quantitative change produces a qualitative change
6. Localization of the genetic defect
a. through experimentation, defect determined to be in Hb molecule
B. Molecular Biology of Sickle Cell Anemia
1. Electrophoresis helped determine details of sickle cell anemia
a. inherited in simple Mendelian fashion
b. incomplete dominance (those with sickle cell trait have half normal RBCs and half sickle cell RBCs)
c. 1st genetic disease localized to a defect in the structure of a specific protein molecule
2. Sickle cell and normal hemoglobin
a. two-dimensional paper chromatography used to determine the peptide fragment of Hb that was different between normal and sickle cell RBCs (Linus Pauling)
b. Vernon Ingram determined the two Hb molecules differ by 1 amino acid
3. Discovering the difference between normal and sickle-cell Hb
a. Hb made up of 2 alpha and 2 beta chain (4 total) polypeptide chains
b. sickle cell Hb has 2 normal alpha chains; mutation in #6 position of both beta chains
c. protrusion formed by substitued aa at #6 location in beta chains locks into complementary site on other beta chains, linking sickle cell Hb molecules
C. Biogeography and Ecology of Sickle Cell Anemia
1. Unique geographic distribution pattern
a. high frequency of sickle cell anemia in families of African descent
b. higher frequency of sickle cell trait in Africa compared to US
c. sickle cell disease in Africa not common - high infant mortality rate for homozygous recessive infants
2. The malarial connection
a. frequency distribution of malaria mapped out closely to that of sickle cell
b. hypothesized in 1954 by Anthony Allison that heterozygous individuals for sickle cell have an advantage in combating malaria over those with normal Hb
c. balanced poymorphism explains how mutant gene (though by itself does not have an advantage) is selected for in the presence of malaria
3. How does sickle cell help combat malaria?
a. asexual reproductive stage of the protozoan consume high amounts of oxygen, as sickle cell become depleted of oxygen, they sickle and are removed from the body by the spleen....along with the merozoites
4. Treatment and Political Aspects
a. continuing search for treatment
b. drug therapies - some success, most limit detrimental effects instead of curing
c. gene Therapy - goal - replace bad gene Hbs with good allele Hba
d. political aspects - less money raised for sickle cell disease compared to predominantly caucasian afflicting diseases (cistic fibrosis and muscular dystrophy)

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

The section on sickle cell anemia (roman numeral five) is a summary of the information provided in this website.

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Unit 1 Evaluation

2008-06-13T21:47:00.003-07:00

1. What were the three aspects of the assignments I've submitted that I am most proud of?
I really enjoyed searching the internet for more information and finding interesting links and photos to add to my compendiums.
I spent alot of time on the entire unit completing the assignments and trying to learn all of the information.
I learned how to use Google Notebook. :) Thanks!

2. What two aspects of my submitted assignments do I believe could have used some improvement?
I need to be more precise with my compendiums.
I need to spend more time on the web links. There is a wealth of information there.

3. What do I believe my overall grade should be for this unit?
A

4. How could I perform better in the next unit?
Well I certainly learned that taking written notes while I read the first four chapters is not efficient. On the second major topic, I started writing my compendium while I read. That worked well. Now I want to continue to tweak and improve my compendiums.

Cell Metabolism & Gene Function: Unit 1 Lab Project

2008-06-13T19:59:00.012-07:00

Introduction
The assignment for our first Lab Project was to build a model of cell.
First I will list the parts of the cell represented in the first section and the function of each. Then I will go through each picture that I took and explain which item is representing each part of the cell.

For the DNA replication, transcripton and translation, my representations varies slightly from my cell model, so I will display addtional pictures that walk through those functions explaining how each component is represented as I go.

List of Cell Parts with Functions
Cell (plasma) membrane - The selectively permeable outer boundary of the cell. It separates the inside of the cell from the outside of the cell and regulates what goes into and out of the cell.
Nucleus - Stores the genetic material. Location of DNA replication and transcription.
Nuclear membrane - Double membrane that separates the contents of the nucleuls from the cytoplasm.
Nuclear pores - Allow movement of ribosomal subunits out of the nucleus and proteins into the nucleus.
Endoplasmic reticulum (ER) - Rough ER is studded with ribosomes on the cytomplas side. After production at the ribosomes, proteins enter the rough ER interior for processing and modification. Smooth ER produces phosolipids. There are no ribosomes on the smooth ER.
Golgi apparatus - Receives proteins and phosolipids from the ER for modification.
Lysosomes - Produced by Golgi apparatus. They fuse with endocytic vesicles, digest the contents, and release them into the cytoplasm.
Vesicle - Membrane-bounded sac that stores and transports different substances.
Mitochondria - The powerhouse of the cell. Produces ATP through the process of cellular respiration.
Microtubule - Part of cytoskeleton. Provide support and aid in movement of organelles around the cell.

Description of Model
I started with a bucket covered with material that was white with gold starts for the nucleus. The material represents the nuclear membrane and the gold stars represent the nuclear pores. The nucleus is sitting on top of a half basket, which represents the plasma membrane (the plasma membrane is labeled in a later photo). Next I added the endoplasmic reticulum. For this I used a wide piece of ribbon and used gold beads to represent the ribosomes that stud the rough endoplasmic reticulum. The smooth endoplasmic reticulum is represented by the area of ribbon without the gold beads. The Golgi apparatus is represented by the blue jean material. Next, I added the lysosomes and vesicles which are represented by the clear, red, and pink beads. For the microtubules I used pipe cleaners, and for the mitochondria I used gold ornaments.Lastly, a picture of the entire cell, showing all of the parts described above.

DNA Replication, Transcription, and Translation
A few additional molecules are required to explain these processes.
Chromosome - DNA in a condensed form. When the DNA is in this compact form, it means they have been duplicated and are ready for mitosis or meiosis.
mRNA - DNA is transcribed into mRNA, which then takes the gentic code to the cytoplasm for translation.
rRNA - Combine with proteins to form ribosomes, which are the location of protein synthesis.
tRNA - Carry anticodons and amino acids to mRNA to aid in protein synthesis.
Ribosomes - Composed of rRNA and proteins; location of protein synthesis.

The nucleus is now represented by the half basket. The gold ribbon with green stripes are the chromosomes. The vertical edges of the ribbon represent the sugar phosphate backbone of the DNA double helix, and the green stripes represent the complementary bases.
This picture shows DNA replication. The double helix has unzipped and two new strands of DNA are being formed as complementary bases of the new strand bond with the bases of the original strand.
Next up is DNA transcription. Here you can see the DNA double helix unzipped at the location of transcription. A mRNA molecule is formed as complementary bases line up with one strand of the DNA. The mRNA is represented by the bold ribbon with the red backbone.
Translation is represented in the last photo. The ribosomal subunits have binding locations for both the mRNA and the tRNA. The codon of the mRNA dictates which tRNA will bond next. There is a specific anticodon on the tRNA that will bind with the corresponding codon of the mRNA. On the other end of tRNA is an amino acid. The polypeptide chain grows as the subunit moves along the mRNA.
Conclusion
Through this lab project, I assembled a large scale model of a cell that included the nucleus and nuclear membrane, the ER, the Golgi apparatus, the mitochondria, and the microtubules, lysosomes, and vesicles. I later constructed a model that represented DNA replication, transcription and translation. This assignment held solidify in my mind what all of these parts of the cell do. I can better visualize both the parts and the processes in my mind.

Unit 1 Ethical Issue: Genetic Technologies

2008-06-13T13:44:00.004-07:00

Pass the Corn Please

Genetic engineering is the altering of genetic material. The purpose of genetic engineering is to produce a new, a better, or more of a "product." The "product" can be anything from insulin, to a salt-tolerant tomato plant, to a new liver. At the heart of genetic engineering is recombinant DNA. Recombinant DNA contains DNA from two or more different sources. To create it, scientists find a gene that has the characteristics that they are looking for, they cut out that segment of DNA, join it to a plasmid, and insert the plasmid into a host cell. As the host cell divides, the gene of interest is cloned, and you end up with, among other things genetically modified food. There exist both benefits and drawbacks over the use of genetic engineering in general, and more specifically over the use of its products in our farmlands, which ends up on our tables.

The benefits of growing genetically modified plants are numerous. Scientists have developed plant varieties that are resistant to herbicides. The benefit of this to the farmer is that weeding is not required and sometimes only one herbicide is required. What this means is that the farmer does not need to till, which contributes to soil erosion, and only one application of a herbicide is required instead of the application of multiple herbicides. Other plant varieties have been engineered to tolerate cold temperatures to prevent the devastating effects of frost. Plant varieties are also being engineered for improved nutrition. For third world countries that rely on one crop as their main source of food, improved nutritional value per serving could help reduce malnutrition.

At the other end of the spectrum is another view of the use of genetic engineering as it relates to our food supply. One of the biggest concerns is about the safety of the food that is produced. In general, there is concern that there is no way to know which products at the grocery store contain genetically modified foods and which do not. Many also believe that genetically modified foods may introduce new allergens, especially in children. Others worry over the impact to the environment. The pest resistant varieties of plants that are being developed could also be inadvertently killing other organisms, along with the pests. It may also be possible for the gene to transfer to other plant species. For instance the herbicide resistant gene could be transferred from the target crop into a weed species. This could make that weed tolerant to the same herbicide.

As you can see, there are valid arguments both for and against the use of genetically modified plants in the food supply chain. There are benefits that range from reducing erosion to improving nutritional value. The biggest arguments against their use are the potential health risks and the potential impact to the environment.

I believe that this argument will continue for some time to come. Research will continue; new variations will be developed and tested. Tests and studies will continue to determine if any concerns are legitimate. Labeling will be improved, so that people will have the option of choosing genetically modified food or choosing non-genetically modified food. Profit, in the end, will determine whether the use of genetically modified plants continues.

Gentics: Online Lab #2

2008-06-13T07:25:00.008-07:00

The human genome is made up of 15,000 genes that exist on 23 pairs of chromosomes. Each parent contributes one of each chromosome to their offspring. It is our genes that dictate so much of who we are today. Everything from the length of our fingers, to the color of our eyes, to whether or not certain protein receptors in our plasma membrane work correctly is determined by our genes. The variations that exist for any given gene are called alleles. Although both parents pass on to us one of every gene, not every allele that we receive is expressed as a trait in our phenyotype. In order for a recessive allele to be expressed, a person must receive the recessive allele from both their mother and father. If one dominant allele is received, the dominant phenotype will prevail.

When looked at from an evolutionary perspective, the genes we have today were "selected" for by nature. They provided our ancestors some advantage over others, such that they were able to reproduce and pass on those genes.

The purpose of this lab was to confirm my understanding of how genes are inherited and how those genes affect the adult phenotype.

First, I will start with the definitions.
1. Genotype - the genes of an individual. When looking at one trait that is coded for by one set of alleles, the genotype is represented by 2 letters. One letter stands for the allele received from the mother, the other letter represents the allele received from the father. For instance, in the case of the fruitfly, the 3 genotypes in scenario 5 were Ll, LL, and ll.
2. Phenotype - the physical appearance of the trait that is expressed through the genotype. Back to the fruitfly, the 2 phenotypes that could be expressed by the 3 genotypes are as follows: LL=long-winged, Ll=long-winged, ll=vestigial-winged.
3. Allele - variations of the same gene. A few examples of alleles from dragon lab are horns vs no horns, wings vs no wings, scales vs no scales. There are dominant alleles and recessive alleles. If an individual has at least one copy of the dominant allele, the dominant allele will be expressed. For the recessive allele to be expressed, the individual must have both copies of the recessive allele. (Unless it is an x-linked allele in males) The alleles for a given trait occur at the same loci of homologous pairs.
4. Cross - refers to taking the genotype of a set of parents and determing the possible genotype/phenotype of their offspring through the use of a Punnett Square. For example, in scenario 5, we crossed a heterozygous long-winged fly (genotype=Ll) with a heterozygous long-winged fly (genotype=Ll).
5. Dominant - when referring to genes and alleles, the dominant allele is one that will express itself any time it is present. In other words, the dominant allele will express itself in the heterozygous individual (1 copy of dominant allele, 1 copy of recessive allele) or in the homozygous dominant (2 copies of dominant allele) individual. In the scenario 5, the dominant allele is long wings. Both parents were heterzygous for this trait. Both had long wings because they each had one copy of the dominant long-wing allele.
6. Recessive - when referring to genes and alleles, the recessive allele is one that will only be expressed in the individual if both copies are present. In the fruitfly lab, the vestigial-wing was the recessive allele. The vestigial-winged fruitfly has 2 copies of the recessive allele for the vestigial-wing.

Here is the screen shot from the dragon lab. In this lab I had to change the genotype (to the right of the dragons) of the second dragon so that its phenotype (physical apperance) matched that of the first dragon.

Here is the screen shot from the Punnett Square lab. This shows the offspring that could result from the crossing of two heterozygous long-winged parents. This visuals shows both the genotype and the phenotype for each individual.

Hair color. Hairline. Eye shape. Eyelash length. Freckles. Ability to roll your tongue. All of these things are human traits that are coded for in an individuals genes, all of which are passed down from the parents. Each parent supplies half of an individual's genome. This is possible through the process of meiosis. Meiosis includes 2 phases of nuclear division. It is the 2 phases of nuclear division that allow the gametes to end up with half the genetic information of the parent cell. The first phase separates the homologous pairs into two daughter cells, and the second separates the sister chromatids. In this way, the gamete ends up with only half the genetic information of the parent cell. The full genome is restored once a sperm cell and egg cell join during fertilization. It is the combination of genes that make up who we are. The combination is also what provides for so much variation between individuals.

Compendium Review Unit 1 Major Topic: Genetics

2008-06-11T09:28:00.038-07:00

GENETICS
I. PATTERNS OF CHROMOSOME INHERITANCE
A. Chromosomes and the Cell Cycle
1. Humans - 46 chromosomes, 23 pairs
2. Karyotype - total view of all 23 pairs
3. 1 pair is sex chromosomes
4. The cell cycle
a. interphase (G1, S, G2 stages) normal functions, getting ready to divide, DNA synthesis
b. cell division - mitosis and cytokinesis
From the text, figures 18.1, showing the karyotype of a male, and 18.2 illustrating the cell cycle.B. Mitosis (for growth, replacement, repair; constant)
1. Prophase
a. chromosomes condense, visible
b. nuclear envelope fragments
c. nucleolus disappears
d. centrosomes move to opposite ends the nucleus
e. spindle fibers appear and attach to centromere
2. Metaphase
a. chromosomes line up along equator of the cell
b. fully formed spindle
3. Anaphase
a. centromeres split
b. sister chromatids separate (now chromosomes)
c. chromosomes move toward opposite poles of spindle
4. Telophase
a. chromosomes arrive at poles
b. chromosomes -> indistinct chromatin
c. spindle disappears
d. nucleoli reappear
e. nuclear envelope reassembles
5. Cytokinesis (split - cytoplasm & organelles, cleavage furrow)
Figure 18.3 from the text provides a nice overview of mitosis.
C. Meiosis (haploid gametes, 2 nuclear divisions)
1. Meiosis I (prophase I, metaphase I, anaphase I, telophase I)
a. synapsis and crossing-over - prophase I
b. homologous pairs align independently at equator - metaphase I
c. homologous pairs separate - anaphase I
c. 2 haploid daughter cells - telophase I
2. Meiosis II (prophase II, metaphase II, anaphase II, telophase II)
Figure 18.7 from the text provides a nice overview of meiosis.
D. Spermatogeneis (production of sperm in males)
1. Primary spermatocyte 2n(meiosis I)
2. 2 secondary spermatocytes n (meiosis II)
3. 4 spermatids n
4. After puberty, continual, 300k / min
E. Oogenesis (production of egg in females - meiosis and maturation)
1. Primary oocyte 2n (meiosis I)
2. Secondary oocyte n and first polar body n
3. Secondary oocyte stops meiosis II at metaphase II
4. Travels to oviduct, completes meiosis II only if fertilized
F. Fertilization
1. Steps
a. sperm swims with flagellum
b. only 1 sperm enters egg,
c. only sperm nucleus fuses with egg nucleus (cytoplasm and organelles from mother)
G. Pre-Embryonic and Embryonic Development
1. Processes of development (cleavage, growth, morphogenesis, differentiation)
2. Extraembryonic membranes (chorion, placenta, allantois, yolk sac, amnion)
3. Stages of development (fertilization to birth)
a. pre-embryonic development (fertilization to appearance of chorion)
b. embryonic development (implantation to eighth week)
Figure 17.3 from the text illustrates pre-embryonic development. Figure 17.4 illustrates embryonic development.
G. Chromosome inheritance
1. Trisomy, monosomy caused by nondisjunction
2. Down Syndrome - autosomal trisomy
3. Changes in sex chromosome #s - Turner, Klinefelter, Jacobs, Poly-X Female
4. Changes in chromosome structure
a. deletion - Williams syndrome, Cri du chat (cat's cry)
b. duplication
c. inversion
d. translocation - Alagille syndrome
II. CANCER
A. Cancer Cells
1. Characteristics
a. lack differentiation (not specialized - epithelial, muscle, nervous, connective)
b. have abnormal nuclei
c. have unlimited ability to divide (telomerase gene turned on)
d. form tumors (no contact inhibition)
e. divide without growth hormones
f. become abnormal gradually (carcinogenesis)
g. undergo angiogenesis and metastasis
2. Cancer is genetic
a. proto-oncogenes become oncogenes
b. tumor-suppressor genes become inactive
3. Types of Cancer (see definition page - sarcomas, lymphomas, carcinomas)
Figure 19.2 illustrates the progression of the tumor.B. Causes
1. Heredity - BRCA1, BRCA2, RET, RB
2. Environmental carcinogens
a. radiation - UV light, X-rays, radon gas
b. organic chemicals - tobacco smoke, pollutants
c. viruses - HepB & C, Epstein-Barr, human papillomavirus
C. Diagnosis
1. Seven warning signs
a. Change in bowel or bladder habits
b. A sore that does not heal
c. Unusual bleeding or discharge
d. Thickening or lump in breast or elsewhere
e. Indigestion or difficulty swallowing
f. Obvious change in wart or mole (ABCD)
g. Nagging cough or hoarseness
2. Routine screening
a. Self-exam (breast and testicle)
b. Colonoscopy
c. Mammogram
d. Pap smear
e. PSA
3. Tumor marker tests - blood tests for tumor antigens/antibodies
4. Genetic - test for mutations in proto-oncogenes and tumor-suppressor genes
The image below shows the crystal structure of the human hepatitis B virus capsid. The reference can be found here.D. Treatment
1. Standard therapies
a. surgery
b. radiation - localized therapy, causes chromosomal breakage, disrupts cell cycle
c. chemotherapy - treats the whole body, damages DNA, interferes with DNA synthesis
d. bone marrow transplant
2. New therapies
a. immunotherapy
b. p53 gene therapy
III. PATTERNS OF GENETIC INHERITANCE
A. Genotype and Phenotype
1. Genotype - genese of an idividual
2. Phenotype - visible expression of a genotype
B. One- and Two-Trait Inheritance
1. Forming the gametes
a. gametes carry half the chromosomes
b. gametes carry allele for each trait
2. One-trait crosses (Punnett square, genotypic and phenotypic ratios, probability)
3. Two-trait crosses (dihybrid cross, probability)
4. Family pedigrees for genetic disorders
5. Genetic disorders of interest
a. Autosomal recessive (Tay-Sachs, CF, phenylketonuria, sickle-cell disease)
b. Autosomal dominant (Marfan syndrome, Huntington disease)
Figure 20.6 from the text shows the resulting offspring when crossing two dihybrids. C. Beyond Simple Inheritance Patterns
1. Polygenic inheritance (polygenic traits=>continuous variation of phenotypes)
a. dominant allele codes for a product
b. skin color
c. multifactorial disorders - controlled by polygenes that are subject to environmental influences (Himalayan rabbits)
2. Incomplete dominance (wavy hair) and codominance (AB blood type)
3. Multiple allele inheritance (ABO blood types)
D. Sex-Linked Inheritance
1. X-linked alleles
a. in males, always inherited from mother
2. Pedigree for X-linked disorders
a. recessive disorders more often expressed in males b/c the Y chromosome lacks the allele
b. color blindness
c. muscular distrophy
d. hemophelia
Figure 20.18 from the text shows the pedigree for color blindness and lists ways in which to recognize a recessive X-linked disorder.IV. DNA BIOLOGY AND TECHNOLOGY
A. DNA and RNA Structure and Function
1. Structure of DNA
a. double helix
b. 2 backbones - sugar-phosphate
c. complementary base pairs = "ladder rungs" (purines=AG, pyrimidines=TC)
2. Replication of DNA
a. process of copying a DNA helix
b. double helix unwinds and unzips, each is a template (semiconservative)
c. complementary base pairing
d. 2 identical double helices produced
3. Structure and function of RNA (A,U,G,C)
a. rRNA - produced in nucleus, joins w/proteins to form subunits of ribosomes
b. mRNA - produced in nucleus, carries genetic info from DNA to ribosomes
c. tRNA - produced in nucleus, transfers amino acids to ribosomes
Figures 21.2 and 21.3 from the text show how, during replication, DNA is unzipped and new complementary bases of the nucleotides pair up to the old strand.
B. Gene Expression
1. Structure and function of proteins
a. made of 20 different proteins
b. determine structure and function of cells in our body
2. Transcription (nucleus)
a. section of DNA is template for production RNA molecule
b. resulting RNA has sequence of complementary bases and U takes the place of T
3. Translation (cytoplasm)
a. tRNA molecules contain anticodons, complementary to codons on mRNA
b. tRNA contains amino acid at other end
c. order of condons on mRNA dictate order of tRNA amino acids
d. occurs at ribosomes
4. Regulation of gene expression (not all genes on all the time)
a. transcriptional control - in nucleus, chromatin density and transcription factors
b. posttranscriptional control - in nucleus, mRNA processing
c. translational control - in cytoplasm, differential ability of mRNA to bind to ribosomes
d. posttranslational control - in cytoplasm, changes to the protein to make it functional
Figures 21.11 and 21.13 from the text illustrate the process of polypeptide synthesis and and overview of gene expression.
C. Genomics
1. The human genome has been sequenced - order of 3 billion base pairs, 25k genes
2. Functional and comparative genomics - how do our genes function, how do they compare to other species?
3. Proteomics and bioinformatics
4. A person's genome can be modified (ex-vivo & in-vivo gene therapy)
D. DNA Technology
1. Genes can be isolated and cloned (recombinant DNA)
2. Specific DNA sequences can be cloned (polymerase chain reaction)
3. Biotechnology products / genetic engineering
a. bacteria - insulin, human growth hormone, hepB vaccine
b. plants - insect and herbicide resistant, salt-tolerant plants
c. animals - bovine growth hormone, gene pharming, xenotransplantation
The photograph below is of Dolly, the first cloned mammal. I. PATTERNS OF CHROMOSOME INHERITANCE
Mitosis and meiosis - very similar, yet very different processes. To start, here is a fun animation along with a real life video that walks through the steps of mitosis. On the same website is an animation for meiosis. You can either play the video straight through or use the step buttons to walk through each phase. I am going to walk through a few of the differences between mitosis and meiosis. First, in meiosis, there are two nuclear divisions whereas in mitosis there is only one. That means that meiosis produces four daughter cells and mitosis produces only two. The four daughter cells from meiosis are haploid cells and the two daughter cells from mitosis are duploid. The daughter cells from meiosis are not genetically identical to the parent cell; they only have half the number of the parent cell. The daughter cells from mitosis are genetically identical to the parent cell. Meiosis occurs in sex cells and the purpose of it is to produce gametes. Mitosis occurs in automsomal cells and the purpose of it is for growth, for replacement and for repair. (Mader 2008)

Definitions for chapter 18 can be found here.

II. CANCER
In 2005, cancer was the #2 leading cause of death in the US. With statistics like that, it seems like a no brainer - put into practice the recommended preventions of cancer. The text breaks down the list into two sections: Protective Behaviors and The Right Diet. A few behaviors one can change to help prevent cancer are to avoid smoke/smoking, avoid the sun and tanning beds, avoid alcohol and radiation, and be aware of occupational hazards. Many studies show that following a certain diet can also help in the prevention of cancer. Things like avoiding obesity, eating plenty of high-fiber foods, increasing consumption of foods rich in vitamins A & C, and including vegetables from the cabbage family in the diet. The American Cancer Society is a great resource for more information on prevention and detection.

Definitions for chapter 19 can be found here.

III. PATTERNS OF GENETIC INHERITANCE
Sex-linked inheritance is different from autosomal inheritance in that male offspring only receive one allele for a given trait. That allele is passed to them from their mother. The Y chromosome that he received from his father does not carry an allele for that trait. In this way, males have a 50% chance of inheriting an X-linked recessive disorder if their mother is heterozygous. If he inherits the recessive allele from her, it will always express itself, since that is the only allele for that gene he will receive. The case is different for the daughter, who, without an affected father, has a zero percent chance of inheriting the disorder. She does, however, have a fifty percent chance of being a carrier. (Mader 2008)

Definitions for chapter 20 can be found here.

IV. DNA BIOLOGY AND TECHNOLOGY
Transcription and translation. This is another area of biology that has me in complete amazement. The fact that we understand how our genes are copied and translated into proteins...the idea renders me speechless. And here it, my general overview. Transcription is the process by which a segment of RNA is made from a segment of DNA. The portion of the double helix that is to be transcribed unwinds and unzips so that the "ladder rungs" or bases are exposed. The exposed bases allow the complementary base pairs that will join to form RNA to line up in the correct order. RNA polymerase joins the nucleotides together to form RNA. rRNA, mRNA, and tRNA are all made in the nucleus in the same way. After production and processing, the 3 types of RNA move to the cytoplasm. mRNA finds the ribosomes (rRNA plus proteins) where translation occurs. Translation is the production of a polypeptide chain; the order of the amino acids in the chain is determined by the order of condons on mRNA. Codons are made up of three bases on mRNA. A codon of mRNA will only bind with the corresponding anticodon of tRNA. Each anticodon correlates to an amino acid that tRNA also carries. As mRNA moves through the ribosome, the codons pair with anticodons. The amino acid that was associated with that anticodon on tRNA gets added to the polypeptide chain. In this way, mRNA dictates the order of amino acids in a polypeptide chain.

Chapter 21 definitions can be found here.

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Compendium Review Unit 1 Major Topic: Cells

2008-06-09T09:01:00.054-07:00

CELLS
I. BASIC CHARACTERISTICS OF LIFE
A. 7 Characteristics
B. Humans are related to other animals
C. Science and social responsibility
II. THE CHEMISTRY OF LIFE
A. What are molecules made of?
B. Importance of water
C. Carbohydrates
D. Lipids
E. Proteins
F. Nucleic acids
III. CELL STRUCTURE AND FUNCTION
A. The fundamental unit of life
B. Ancestors of animal cells
C. The gate
D. The control center
E. The infrastructure
F. The powerhouse
IV. TISSUE TYPES AND HOMEOSTASIS
A. Supports and connects
B. Moves and beats
C. Sends, receives and processes
D. Protects
E. The goal of organ systems

THE BASIC CHARACTERISTICS OF LIFE
One of the main points that I have learned from this unit is that life has evolved. The fact that the characteristics of life can be compiled into a short list of seven helps one to understand that all living things were created from the same single cell. It is mind-boggling: Every living thing on this Earth can be identified as living by only seven characteristics. And those 7 characteristics are that living things: 1. Are organized, 2. Take materials and energy from the environment, 3. Reproduce, 4. Grow and develop, 5. Are homeostatic, 6. Respond to stimuli, 7. Have an evolutionary history (Mader 2008). Figure 1.2 from the text (Mader 2008)does a great job in showing how life is organized all the way from an atom up to the Earth's biosphere. The idea of how acquiring materials and energy is needed by all living things can be understood by looking at humans and food intake. Humans eat for many reasons, but the actual need is at the cellular level. Cells need nutrients from food to produce the energy to run the processes that keep them alive. The same is true of a single celled prokaryote. One goal of all living things is to reproduce or to pass on their genes to the next generation. Once a new organism is produced, it must grow and develop so that it can also take in materials, produce energy, and eventually pass on it's genes as well. Along the way, it must maintain homeostasis, so that all of the processes required to produce energy, to grow, to develop, and to reproduce and run normally. If homeostasis is not maintained, proteins will break down, processes will cease, and the internal systems will stop functioning properly. Linked closely to homeostasis is the ability to respond to stimuli. As an organism's outside environment changes, it needs to be able to make adjustments that allow it to maintain homostasis. In order to do this the organism must have a way of notifying its internal systems and then make changes accordingly. And lastly, evolution "explains both the unity and the diversity of life. All organisms share the same characteristics of life because their ancestry can be traced to the first cell or cells. Organisms are diverse because they are adapted to different ways of life" (Mader 2008).

Over time, scientists have developed a classification system into which all organisms can be placed. Taxonomy is built upon the basic fields of morphology, physiology, ecology, and genetics (source1). The system starts with the 3 very broad domains. They are the Eukarya which have a membrane-bounded nucleus and the Archaea and Bacteria which both lack a membrane-bounded nucleus. Within the domain Eukarya are the four kingdoms Animalia, Plantae, Fungi, and Protista. Humans are mammals in the vertebrate class which is part of the kingdom Animalia. Humans are distinguished from other Eukaryotes because we have a nerve cord that is protected by a vertebral column which has repeating units. This indicates that we are segmented animals (Mader 2008).

Part of what separates humans from other mammals also makes us dangerous to our biosphere. We have highly developed brains, we use creative language and we have the ability to use a wide variety of tools. Among others, these factors have allowed us to continue to make significant technological advances over the course of our history. While many of these discoveries have enriched our lives, many have also negatively impacted our environment. Humans are constantly modifying our environment and impacting the biodiversity of our planet.

As mankind continues to make exciting new advances, it becomes increasingly more important for everyone to be educated and take a stand on the ethical issues that these new advances bring to light.

THE CHEMISTRY OF LIFE
Molecules, although small in size, can be broken down into even smaller parts. Learning a few basic definitions in chemistry will help to explain this. Matter is anything in this world that has mass and takes up space. It refers to living organisms as well as inanimate objects. One of the basic building blocks of matter then is the element and the smallest unit of an element is the atom. Atoms are made up of protons, neutrons, and electrons. Protons carry a positive charge, electrons carry a negative charge, and neutrons are electrically neutral. The protons and neutrons are located in the nucleus of the atom and the electrons circle the nucleus in electron shells. Atoms are most stable when their outer shell is filled with 8 electrons. Electrons in the outer shell can be shared with other atoms (covalent bonding) or one atom may give up an electron and another atom can accept it (ionic bonding). These two types of bonds are what allow atoms to form molecules and compounds.

One very common compound is water, which is made up of two hydrogen atoms and one oxygen atom. The 6 electrons in the outer shell of the oxygen atom and the 2 electrons (total) from the 2 hydrogen atoms bond covalently to fill the outer shell of each atom. The oxygen atom, because it is a larger atom, has a greater ability to attract the electrons towards it. This causes the water molecule to be polarized, meaning the oxygen side of the molecule has a slightly negative charge and the hydrogen side of the molecule has a slightly positive charge (Mader 2008). Because of this polarity, the hydrogen side of the molecule is attracted to a negatively charged atom, even at some distance away. This attraction is called a hydrogen bond (Mader 2008). Figure 2.7 from the text illustrates the polarity how the polarity of water allows hydrogen bonds to form.The polarity and hydrogen bonding are what allow water to have the following crucial characteristics that are so important to life. 1. Water is liquid at room temperature, so we can drink it. 2. The temperature of liquid water rises and falls slowly, preventing sudden or drastic changes. 3. Water has a high heat of vaporization, keeping the body from overheating. 4. Frozen water is less dense than liquid water so ice floats on water. 5. Water molecules are cohesive, so liquids fill vessels such as blood vessels. 6. Water is a solvent for polar molecules, and thereby facilitates chemical reactions both outside and inside of our bodies (Mader 2008).

Cells in every living organism are composed of four organic molecules or molecules that contain carbon and hydrogen. They are carbohydrates, lipids, proteins, and nucleic acids. When a cell builds or breaks down organic molecules, it uses a dehydration reaction and hydrolysis reaction, respectively. A dehydration reaction removes a hydroxyl group (-OH) and a hydrogen atom (-H) from the subunits that are involved to form the molecule. A water molecule is also formed. A hydrolysis reaction takes a water molecule and adds it back (in the form of a hydroxyl group and a hydrogen atom) to the subunits of the molecule to break it down (Mader 2008).

The first of the four molecules of life is the carbohydrate. Carbohydrate molecules are characterized by the presence of the atomic grouping H-C-OH in which the ratio of hydrogen to oxygen is approximately 2:1. Their purpose is for quick and short-term energy storage in all organisms (Mader 2008). Carbohydrates range in structure from simple to complex. Simple carbohydrates or simple sugars are those that have from 3 to 7 carbon atoms. A disaccaride is also considered a simple sugar. It consists of 2 monosaccarides that have joined together by dehydration. Complex carbohydrates or polysaccharides are macromolecules that contain many glucose units joined together. A few examples of polysaccharides are starch, glycogen, and cellulose (Mader 2008).

The second molecule of life is the lipid, another energy storage molecule, but energy storage is not their most significant function. The most important characteristic of lipids is that they do not dissolve in water because, in general, they are not polarized. Lipids are found as fats and oils, as steroids, and as phospholipids. These three groups of lipids differ from each other in structure and function. When 3 fatty acids (molecule of a carbon-hydrogen chain that ends with the acidic group -COOH) combine with 3 molecules of glycerol by dehydration, a fat molecule and 3 water molecules are produced (Mader 2008). In the body, fat molecules are used for long-term energy storage, insulation, and cushioning. Steroids, on the other hand, are molecules that have a backbone of four fused carbon rings. Steroids differ from each other based on functional groups that are attached to the backbone. One example of a steroid is cholesterol which serves as a component of the plasma membrane in animal cells and is also the precursor to other steroids (Mader 2008). The last group of lipids is the phospholipids. Phospholipids are made up of two fatty acids and a phosphate group. The fatty acids are nonpolar and are therefore hydrophobic. The phosphate group is ionized and is therefore hydrophilic. It is the structure of the phospholipid that allows it to carry out what could arguably be the most significant function that lipids do. The hydrophobic tails and the hydrophylic heads form a bilayer in watery solutions. The tails face towards each other and the heads face the solution. In this way, phospholipds form the plasma membrane of every living cell. The pictorial below taken from this website shows how the phospholipid bilayer can form a plasma membrane.
The third molecule of life is the protein. Proteins have many functions, such as providing structural support, catalyzing reactions, transporting substances into and out of the cell, protecting the body by 'attacking' antigens, regulating homeostasis, and causing muscles to contract (Mader 2008). Proteins are made up of subunits called amino acids. An amino acid is made up of a carbon atom that is bonded to a hydrogen atom, an amino group, a acid group and an R group. Amino acids are joined together through peptide bonds. The linear sequence of peptide bonds (polypeptide )is what constitutes the primary structure of the protein. There are at least two and sometimes three additional levels of organization that define a protein. The secondary structure is the orientation that the polypeptide takes on. There are two types: the alpha helix or the pleated sheet. The tertiary structure of a protein is its final three-dimensional shape. Whatever the final shape may be, the hydrophobic sections stay towards the inside while the hydrophilic sections stay towards the outside. When two or more polypeptides join together, the quaternary structure is formed. Not all polypeptides join with others to for the quaternary structure. Figure 2.20 from the text provides an overview of each level.The folding of amino acids into proteins is one area that remains a mystery to scientists. For the most part, they have not been able to figure out why a protein folds up the way it does. Much time, energy and resources have been and still are being put into this field of biology. One example is the Blue Gene project out of IBM and another is the Folding@home, distributed computing project out of Stanford University. This area of study is so important to the understanding, treatment, and possible prevention of many diseases that develop when a protein does not fold up correctly.

Last but not least in the list of molecules of life are the nucleic acids. DNA and RNA are the two types of nucleic acids. The difference in structure between the nucleotides of the two is essentially given in their names. DNA stands for deoxyribonucleic acid and the pentose sugar that it contains is deoxyribose. RNA stands for ribonucleic acid and the sugar that it contains is ribose. The nucleotides of DNA and RNA each also contain a nitrogen-containing base and a phosphate. There are four types of bases in DNA: adenine, thymine, guanine, and cytosine. In RNA uracil replaces thymine (Mader 2008). The other 3 bases are the same. The sugar of one nucleotide bonds with the phosphate of the next to form the backbone of polynucleotide strand (Mader 2008). In DNA, two strands bond via hydrogen bonds between the bases to form a double helix. The same bases always pair together (complementary base pairing): A-T and G-C (Mader 2008). Complementary base pairing allows DNA to replicate in a way that ensures the sequence of bases will remain the same (Mader 2008). It is the sequence of bases that determine the sequence of amino acids in a protein (Mader 2008). RNA is single stranded and forms through complementary base pairing with DNA (Mader 2008). Nucleic acids are also involved in cell metabolism. ATP is adenosine plus three phosphate groups. The first image shown below taken from the text shows the 3 subunits of a nucleotide. The image below it, figure 2.21 from the text, shows the sugar phosphate backbone plus complementary base pairing of DNA.
CELL STRUCTURE AND FUNCTION
The cell theory tells us 3 things: 1. A cell is the basic unit of life, 2. All living things are made up of cells, 3. New cells arise only from preexisting cells. There is much depth behind these three seemingly simple statements. What you can take from these three statements is that the fundamental unit of life, the cell, connects us to all other living things. It is a mind boggling concept. The development of the compound microscope played a huge role in the discoveries that led to the development of the cell theory. In addition to the 2 dimensional, magnified views that the compound microscope provides, scientists today can also view a magnified 3d image of the surface of an object with the use of a scanning electron microscope. Although the image seen with the use of a transmission electron micrscope is only 2d, the magnification power and resolving power are much greater than those of a compound light microscope.

Before diving into a discussion of the many organelles that make up a eukaryotic cell, it is important to understand the origin of these organelles. Unlike eukaryotic cells, the prokaryotes (archaea and bacteria) lack a nucleus. It is believed that the eukaryotic cell evolved from the archaea (Mader 2008). The University of Arizona has an informative and humorous tutorial on Prokaryotes, Eukaryotes, and Viruses. I especially enjoyed this page. It is theorized that the nucleus of the eukaryotic cell was first created from a bit of the plasma membrane breaking off inside the cell and surrounding the DNA. I think of it as a process similar to endocytosis. Figure 3.3 from the text depicts how the evolution from archaea to eukaryote may have occurred. I like to think of the plasma membrane as the gate that surrounds the cell. It provides the boundary between the inside and the outside of the cell. It is the phospholipids that come together to form the bilayer that is the plasma membrane. It keeps the cell intact and is selectively permeable - that is - it only allows certain molecules and ions to enter and exit the cytoplasm freely (Mader 2008). One method by which molecules can cross the membrane freely is by diffusion, which is the movement of molecules from an area of higher concentration to an area of lower concentration. Osmosis is the term used to describe the diffusion of water across the membrane. The 'gate' can not move all the molecules by itself though. This is where the gatekeepers come in. Proteins, or the 'gatekeepers,' embedded in the plasma membrane move molecules from outside the cell to the inside or vice versa using 2 methods, facilitated transport or active transport. The carrier proteins involved in facilitated transport move molecules down their concentration gradient at a rate higher than diffusion. Because the molecules are moving down their concentration gradient, no energy is expended during facilitated diffusion. Active transport on the other hand moves molecules against their concentration gradient. This requires the expenditure of energy. Like facilitated transport, carrier proteins, now called pumps, have an affinity for a certain type of molecule. That is to say that a carrier protein binds with a specific molecule. Two additional methods that move molecules across the membrane are endocytosis and exocytosis. Both involve invagination of the plasma membrane. A pouch is formed around the molecules to be moved and eventually the pouch splits off from the membrane to form a vesicle that houses the molecules. Endocyctosis is the movement of molecules from the outside to the inside of the cell and exocytosis is the movement from the inside to the outside. Figure 3.5 from the text illustrates the fluid-mosaic model of plasma membrane structure.Just as the plasma membrane is the gate that surrounds the cell, in my mind, the nucleus is the control center. The nucleus is where the genetic code is stored in the form of DNA. Remember, it is the genetic code, or the genes, that specify the sequence of the amino acids in proteins (Mader 2008). And proteins control cell metabolism. The nucleus has its own membrane, called the nuclear envelope, separates its contents from that of the rest of the cell. The nuclear envelope is a double membrane that is continuous with the endoplasmic reticulum and contains nuclear pores that allow the passage of ribosomal subunits out of the nucleus and proteins into it (Mader 2008). Through an electron microscope, DNA is only visible in the form of chromatin, which consists of DNA and associated proteins. The nucleus also contains nucleoplasm and nucleoli. The nucleolus is the site of rRNA production and where it joins with proteins to form the subunits of ribosomes (Mader 2008). Figure 3.11 from the text shows a drawing of the nucleus with its various components along with two electron micrographs. The one to the left shows the nuclear pores and the one to the right shows both rough endoplasmic reticulum (ER) and smooth ER. Ribosomes are where protein synthesis occurs. There are ribosomes that are attached directly to the endoplasmic reticulum and others that are floating in the cytoplasm. The endoplasmic reticulum is part of the endomembrane system. The endomembrane system consists of the nuclear envelope, the ER, the Golgi apparatus, lysosomes, and vesicles. Once proteins are synthesized in the ribosomes, they enter the rough ER interior for processing and modification (Mader 2008). The smooth ER produces produces phospholipids and carbohydrates. The Golgi apparatus look like stacks of pancakes and they process, package and delivery proteins and lipids received from the ER. Lysosomes are sacs produced by the Golgi apparatus that contain digestive enzymes. Vesicles are small membranous sacs that transports substances. Figure 3.12 from the text is a great illustration of the endomembrane system. To me, the cytskeleton is the infrastructure of a cell. It provides support, it anchors things down, and it can aid in movement. The cytoskeleton is a collection of protein fibers that crisscross the cytoplasm (Mader 2008). Microtubules, actin filaments and intermediate filaments are all examples of the fibers that make up the cytoskeleton. Cilia and flagella are both made up of microtubules and aid in movement. Cilia are about 20 times shorter than flagella. Ciliated cells line our respiratory tract and a female's oviduct. Sperm cells are flagellated (Mader 2008).

Last but not least is the powerhouse of the cell. So called because mitochondria convert the chemical energy of glucose into energy the cell can use (the chemical energy of ATP molecules) (Mader 2008). This reaction is called cellular respiration. Cellular respiration includes glycolysis, the citric acid cycle and the electron transport chain. During glycolysis (anaerobic), glucose is split into two molecules of pyruvate. NADH results from hydrogen and electrons being removed from glucose. This reaction also nets 2 ATP molecules. The cytric acid cycle (aerobic) completes the breakdown of glucose and again, NADH carries away the hydrogen and electrons and 2 more molecules of ATP are produced. Carrier proteins of the electron transport chain (aerobic) accept the electrons from NADH. The net result of cell respiration is the production of 36 ATP molecules. Proteins, carbohydrates, and lipids can also be used to fuel cellular respiration. Figure 3.14from the text shows a mitochondria. The matrix contains enzymes to break down glucose and ATP production occurs at the cristae.When the body can not bring in enough oxygen to support cellular respiration, it switches to the process of fermentation to produce energy. During fermentation, glycolysis still occurs and the resulting hydrogens and electrons are still passed to NAD. When the electron transport chain is not available due to a lack of oxygen, NADH passes the hydrogens and electrons to pyruvate. The result is the production of lactate and only two molecules of ATP. Fermentation works well for bursts of energy for a short time, but as lactate builds up, muscles begin to fatigue and cramp. The energy that is produced during cell respiration or fermentation is used to power all of the processes that keep it alive. The link to the E.Coli metabolic overview map is a bit overwhelming. I am still trying to get a handle on the fact that all of those processes are happening inside of one bacteria...and that there is a protein that catalyzes each reaction. It is mind boggling.

Tissues are made up of specialized cells of the same type that perform a common function in the body (Mader 208). The first of four tissue types is the connective tissue. The main function of connective tissue is to connect and support. The three types of connective tissue, fibrous, supportive, and fluid, are all made of specialized cells, ground substance, and protein fibers. Fibrous connective tissue can be broken down further into 3 main groups: loose fibrous (protects internal organs), adipose tissue (insulates and protects kidneys and heart), and dense fibrous (tendons, ligaments). Supportive connective tissue includes the cartilages: hyaline (nose, long bones), elastic (ear), and fibrocartilage(disks in back, knee) and bone. Fluid connective tissue consists of blood and lymph. The red blood cells transport oxygen, white blood cells fight infection, and platelets form clots. Lymph is a clear watery fluid derived from tissue fluid that contains white blood cells (Mader 2008).

There are three types of muscle tissue: skeletal, smooth, and cardiac. Skeletal muscle is attached to the skeleton and causes movement in the body when it contracts. Skeletal muscle is striated. Smooth muscle is found in the walls of the viscera (intestine, bladder) and blood vessels (Mader 2008). It contracts slowly and is involuntary. Cardiac muscle is only found in the walls of the heart. Figure 4.5 illustrates and explains the three types of muscle tissue.

Nervous tissue is made up of nerve cells (neurons) and neuroglia, which support and nourish the neurons (Mader 2008). A neuron is made up of three parts. The dendrite receives signals. The cell body houses most of the cytoplasm and the nucleus. The axon conducts nerve impulses. Outside of the brain and spinal cord, fibers (neuron plus myelin) bound by connective tissue form nerves. Neuroglia outnumber neurons nine to one and take up more than half the volume of the brain (Mader 2008).

Epithelial tissue protects. It consists of tightly packed cells that form a tight continuous network. It lines body cavities and covers surfaces. The cells are anchored to a basement membrane. On the other side they are face the environment. Epithelial cells are named based on the number of cell layers and the shape of the cell (Mader 2008). There is also transitional epithelium, which changes in response to tension (urinary bladder), and glandular epithelia secretes a product (goblet cells, sweat glands) (Mader 2008). Figure 4.7 from the text shows some examples of basic epithelial tissue and where you will find each.
All of these tissues fit together in different ways to form the organs of the body. As we learned in chapter 1, our organs work together to form the organ systems. It is our organ systems working together that help us to maintain homeostasis. The nervous system processing input from the environment and along with the endocrine system, directs the rest of the organ systems. Figure 4.15 shows a great overview of what each of the major organ systems do to contribute.

REFERENCES:
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).

Links provided throughout the summary take you to online sources.

IMPORTANT NOTE: Any time "text" or "the text" is referenced in the above summary, I am referring to the textbook Human Biology by Sylvia Mader (cited directly above).

Cells: Online Lab #1

2008-06-08T18:44:00.011-07:00

Although the use of tools to magnify objects appears to date back to Egyptian times,credit for the first compound microscope is generally given to Zacharias Janssen (source1). This invention was a significant one for the field of science. It opened up a whole new world to the scientists of the time. The microscope's importance to the field of biology continues today. Robert Hooke is another notable scientist who's interest in everythings science drove him to develop the iris diaphragm along with one of the best compound microscope and illumination systems of his time (source4). He is also well known for his book Micrographia in which he provdes a detailed record of his observations of organisms that he viewed under his microscope (source4). Another man of note is Anton van Leeuwenhoek who is discovered, among other things, bacteria, free-living and parasitic microscopic protists, sperm cells, blood cells, and much more (source5). He is also well-known for his skill in producing less complicated, but highly powerful for the time, single lens microscopes (source5).

For students new to biology, one of the most important set of skills to learn is how to use and care for a compound light microscope. The purpose of this lab is to gain these skills.

But before learning how to use the microscope, one should also understand how it works. This can be explained by going through the functions of just a few of the parts of the microscope. The condenser is a lens systems that focuses and aligns light from the light source onto the specimen (source2). The light transmits the image through the objective lens which brings the image of the specimen into focus (source3). The image is then further magnified as it passes through a second set of lenses called the ocular lenses (source3).

Now onto the lab. As instructed, I viewed the video presentation, completed the tutorial, and viewed the 4 slides. After doing so, below is my understanding of how the parts of a microscope work.

1. Stage - The stage is the platform onto which the slide is placed. It holds the slide/specimen level. The stage is adjusted by turning either the coarse adjustment knob or the fine adjustment knob. I only adjust the stage height using the coarse adjustment knob when looking at the microscope.
2. Focus knobs
a. Coarse adjustment knob - The coarse adjustment knob is used to bring the specimen into the focal plane of the objective lens (source2). The coarse adjustment knob is adjusted by turning the top either away from yourself (to raise the stage) and towards yourself (to lower the stage). The coarse adjustment knob should only be used while looking at the microscope.
b. Fine adjustment knob - The fine adjustment knob is used to bring the image into focus. The fine fine adjustment knob is adjusted by turning the knob. Turning the knob raises and lowers the stage in very small increments. The fine adjustment knob can be used while looking through the microscope.
3. Iris - The iris controls the amount of light that is projected from the light sourse onto the specimen. The amount of light that passes through the iris is adjusted by moving the lever located under the stage from sided to side. Depending on the model, the microscope may have a diaphragm instead of an iris. The diaphragm has pre-drilled holes in a metal plate that also vary the amount of light that reaches the specimen. The amount of light passing through the iris can be adjusted while looking through the microscope, but caution should be taken. A minimum amount of light should be let through initially to protect the eyes from bright light.
4. Oculars - The oculars are the part of the microscope that you look through. They contain lenses that further magnify the image transmitted from the objective lens. The distance that the oculars are from each other are ajusted by sliding one of the oculars towards or away from the other. They should be adjusted until the the two circles of light line up to form only 1 circle. The distance of the oculars should be adjusted while looking through the microscope.
5. Objectives - The objective lens gathers light from the specimen and magnifies the image. There are ususally at 3 objective lenses on a compound light microscope that each provide different levels of magnification. When viewing a specimen, you should always start with the lowest magnification and move up to the highest, centering and focusing the image as you move along. You move from one objective to the next by turning the nosepiece. The objectives should be changed when looking at the microscope.

I chose the cheek smear as the image to post here. You can clearly see one complete cell just north of the centerline. I believe you can see the darker line of the plasma membrance encircling the cell along with the dark spot that is the nucleus. There are about 7 other cells (complete and/or partial parts) that you can see in this image. (You can click on the image to get a larger view.)

This lab was a great introduction to the microscope, and the simulator was amazingly like using a real microscope. Through the readings I was able to get a good grasp of the correct techniques that should be used when handling, using, and storing a microscope in order to protect it for future use. The websites provided along with a few others provided great resources to learn about the parts of the microscope, what the function of each is and how to correctly use each one. Most importantly though, I have found myself fascinated by what things look like at the cellular level and want to view things under a real microscope! I was also fascinated by the images I came across as seen through a scanning electron microscope.

My first entry

2008-05-28T08:47:00.000-07:00

Hello Mr. Frolich and fellow classmates! My name is Sara Stanford. I am taking this class as a prerequisite for the nursing program at Yavapai College. My goal for this class is to master the information that we will navigate through during the next 8 weeks.

Right now my favorite artist is a photographer that I found on Flickr. She takes incredible pictures of people's furry loved ones. Here is her site: Illona. She has a ton of photos, so if you have just a few minutes and want to take a look, I suggest looking through her set labeled "My Favorites."

A few things about myself....I grew up in a farming family in the midwest and worked on the farm every summer from when I was 12 until I was 23. My husband and I have been married for almost nine years, and we have both been racing mountain bikes for about 8 years. I love hiking and riding on the awesome trails in Prescott. I have 3 lovely sisters, 4 nieces, and 2 nephews.