Biology 156

EVALUATION

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REGARDING YOUR OWN PERFORMANCE

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

Both my compendium of course and my first Lab project, it was very fun!

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

Probably my essay and my quizzes

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

an A. I think I have worked pretty hard this semester.

4. How could I perform better in the next unit?

If there was one, probably better or the same.

REGARDING THE UNIT (adapted from Stephen Brookfield, University of St. Thomas "Critical Incident Questionnaire")

At what moment during this unit did you feel most engaged with the course?
I would say chapter 16 & 17. I really got into the project.
At what moment unit did you feel most distanced from the course?
I had to re-read chapter 23, I don't know what I really didn't understand it, but I got it now.
What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
Probably when the teacher told us this unit had to be done but the actual due date and a nice reminder in the emails. thanks!
What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
I would say the main project, I had the hardest time finding the "right lizard" the right "tree"!
What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.) that I finished in time and I started early. I think starting early shows in my work because I had more time to make it look great!

Essay

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This is an image of a swimming pool in Japan. I'd say that this country is overcrowded!!

Is population the problem? And who should reproduce?

I never thought to sit down and think about our population or any countries population and to think we could lose resource to “live”. If our resources are low then yes I would think our population is a problem. Is it everyone’s problem? YES!

A child in the US consumes the same resources as 30 children would in India and 300 in Ethiopia. Other third world countries don’t have the same resources, money, and education like the US does. If other countries are in danger of having diseases, malnutrition and keep producing then each country should try and help the “cause”.

I really do believe that the “under developed” countries need more help about education and the cause of our population. If they had the resources of contraceptives I’m sure that would help a whole lot with their population and help them with their resources, the population won’t be such a big deal.

I’m not sure if anyone has a right to tell anyone “who should reproduce”. It’s they’re choose and their bodies. Instead of tell someone “hey you can’t have any more children” the key is to education, let them know what our future can hold, about limited resources, then let them decide on what they want to do.

I think the developing economy is a problem also but it’s a problem that can’t be stop. We ourselves choose what we eat and how much we eat. We eat what resources we have, fast food, chips, soda while other countries are eating what they find to eat. Third world countries need the developing economies than the US does, for survival. I’m not saying the third world should eat chips and pizza, but need the resources to grow food and to raise animals that give them food.

http://neatorama.cachefly.net/images/2007-08/crowded-pool-japan.jpg

Lab Project: Species

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Lab Project

This lab I will show picture of 20 or more species I interact with on a daily basis. Each will have their picture, scientific name, ecological principle and a explanation of my interaction with them and their interaction with other species.

1. Common Name: Pug
Scientific name: (canis Lupus Familiaris)
Ecological principles: Symbolic
I choose my Pug (homer). He is one of the first animals I see every morning. I follows me around till I feed him and he is small but very protective of me. A pug is a domestic dog, a good pet.

2. Common Name: Chihuahua
Scientific Name: (Canis lupus Familiaris)
Ecological Principles: Symbolic
My other dog, Babygirl. Shes a playful one and likes to hop around when she see anyone. A Chihuahua is a domestic dog.

3. Common Name: Cats
Scientific Name: (Felis silvestris)
Ecological Principles: Symbolic
My cats, a domestic animal (I have three) I had them since they were babies now they are adults and very lazy now but still like to cuddly and play

4. Common Name: Hummingbirds
Scientific Name: (Family Trochilidae)
Ecological Principles: Commerical
I have bird feeds outside so I hear the humming birds a lot in the morning.

5. Common Name: Pigeon-
Scientific Name: (Columba livia)
Ecological Principles: Symbolic
I found this bird injured and now it can’t fly. Instead of leaving for other animals to eat I took it in and feed it. So its my bird. He/she is still scared of me but I still feed it and it slowly getting use to seeing me.

6. Common Name: tumbleweed
Scientific Name: (salsola tragus)
Ecological Principles: commensal
I see tumbleweeds everywhere I go, especially when it’s windy and they blow around. They grow anywhere they please and don’t need a lot of water to grow but die quick from the sun’s heat.

7. Common Name: Yucca-
Scientific Name: ( Yucca baccata)
Ecological Principles: commensal
I see these plants when I go running. I know some people use these plants to make baskets. But Yucca plants are parasitic, don’t need to much rain to grow flowers and can get very tall. These kind of plants are common in Arizona.

8. Common Name: Horse-
Scientific name: Equus caballus
Ecological Principles: Symbolic
My dad’s horse, Tex. This horse is older than I am!! I found horses to be symbolic because its like having a friend and horses can be loyal by not running away or bunking their owner off of them. A horse is an domestic animal.

9. Common Name: Lizard-
Scientific Name: (Urosaurus ornatus)
Ecological Principle: Commensal
My dogs and cats find these lizard around my yard and I find them in my plants. They don’t bother me and I don’t bother them because they usually run away very quick anyways. Lizards are common in the desert especially Arizona.

10. Common Name: Ants-
Scientific Name: (Paratrechina longicornis)
Ecological Principle: Parasitic
When I see outside at times I get bite by one of these and they HURT.

11. Common Name: Juniper tree-
Scientific Name: (Juniperus)
Ecological Principle: Mutualism
I see these trees often around my area. I see them benefiting us in the future for wood, to keep our environment growing, oxygen, and well shade when were hiking. They benefit when they grow tall and stronger.

12. Common Name: Housefly
Scientific name: (Musca Domestica)
Ecological Principle: Commensal
I think only flies’s benefit for themselves. For human and pets, well they are annoying because they fly around our food/drinks and at times around our faces!!

13. Common Name: House plants (roses)-
Scientific name: (Rosa roxburghii)
Ecological Principles: Mutualism
I think people and the plant both benefit from each other. The owners of the plants like having plants around their house and the owners water the plants to make it grow bigger. The plants benefit because humans because the humans water them to keep them alive.

14. Common Name: Cotton-
Scientific name: (Gossypium)
Ecological Principle: Parasitic
People are the only who cut down the cotton plants to makes clothes or other products that humans use. So the people cause harm to the cotton plant.

15. Common Name: Milk-
Scientific Name: (Bos Taurus)
Ecological Principle: Mutualism
Many people drink milk to help with our bones and to grow. The cows we get them from live and the human takes care of them to keep getting milk, so both benefit from each other.

16. Common Name: Corn
Scientific Name: (Zea mays)
Ecological Principle: Mutualism
Both people and the plant benefit from each other. The people eat the corn but the people also help the corn stay alive to keep growing.

17. Common Name: Goldfish-
Scientific Name: (carassius auratus)
Ecological Principle: Symbolic
Both the goldfish and the owner benefit from each other. Many goldfish owners take care of their fish and love it and treat it like a pet. The goldfish like their owners because it’s the owner who feeds them when they get hungry.

18. Common Name: Ticks-
Scientific Name: (Dermacentor variables)
Ecological Principle: Predation
We kill it if it does us harm or our pets. When a dog or cat has to many ticks they can get an infection from them and cause death. It can even bite humans but once we feel it we located it and kills it. They can hold a lot of blood in their tiny bodies and expand but if no blood is around they eventually starve to death.

19. Common Name: Fleas-
Scientific name: (Ctenocephalides cannis)
Ecological Principle: Predation
These little fleas are on animals and cat, usually dogs. They can bite the dogs and the dogs can try to kill them also but chewing around the area that’s bothering them at. The fleas bite the animals for food and survival.

20. Common Name: Rabbit-
Scientific name: (sylvilagus)
Ecological Principle: Commensal
The rabbit usually don’t harm anyone but look for food for survival. Its usually other animals that eat them. Aren’t they cute to look at?

21. Common Name: Crow-
Scientific Name: (corvus brachyrhynchos)
Ecological Principle: Parasitic
The crows eat smaller animals and even creature that are already dead. They feed on them and can kill for food, for their survival.

Population Lab

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Human Population Demographics

This online lab is about demographics. It will show a comparing of the world’s population, fertility rate and mortality rate with one higher fertility rate country and one lower fertility rate country. The rate will be show the date 2050 to see what the population will be like for each country.

What was your high fertility rate country and what was its fertility rate?
I chose Africa because it’s a big continent and have a high rate of fertility rate. The fertility rate in the year 2050 is 5.3 children and the population 2 billion. On the graph it shows that most of the population are between the ages 0 to 19 which is all children.

What was your high fertility rate country and what was its fertility rate?
I chose Africa because it’s a big continent and have a high rate of fertility rate. The fertility rate in the year 2050 is 5.3 children and the population 2 billion. On the graph it shows that most of the population are between the ages 0 to 19 which is all children.

2. What was your low fertility rate country and what was its fertility rate?
I chose Japan because it’s a small country. The birth rate is 1.5 children. The population in the year 2050 is 101 million. On the graph it shows that the birth rate goes down as years go by. Comparing the year 1990 and 2050 the birth rate decreased, showing that the population gets lower each year.
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?
The graph in Africa show that most of the younger generation takes up most of the population and also they are the one producing more children. How it effects the future population is that they younger generation will keep having babies at a young age, giving Africa a higher population each year. One thing to be aware of is that Africa have a high rate of AIDS too, which means more children being born with AIDS and more deaths. The population will be harder to control because of the lack of education, money, hospitals, and housings.
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.
In the United States, many are getting the proper education, knowledge of contraceptives, and have a stead income. During the years of “baby boom” many women were getting pregnant a younger age (still in high school) and the younger generation will want more for themselves and will want to go to college before starting a family of their own. With women being involved with their careers and men wanting to wait, and both wanted to have a better education, can delay childbearing till their late twenties to early thirds. The advertisement of college is very helpful too because the younger generation will want to go to college, have some independent before they are ready to settle down to have a family.
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.
Middle Age:
I think the people will be more educated, responsible, creative with streets and buildings, clean, concern with the environment, caring and loving, good income, have good knowledge of life, less violence, less drinking and drug use, and a friendlier community.

Lots of Children:
More crimes, low education, unmotivated, less income, dirty communities, no care of the environment, less responsible, rude and mean, have more excitement in life, loud, have an intense life, and single parents.

Conclusion:
I noticed that each country is different from one another because they each live and grow in different environments. Also I noticed that in the year 2050 the population for the world will keep increasing and it will be overcrowded making it hard to survive because people will eat more and the farming will get smaller. To help with the population in each country I think they need to understand what our future holds and give them a proper education and knowledge.

Chapters 22,23,24

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Chapter 22

Human Evolution

Table of Concepts

Origin of Life
Biological Evolution
Classification of Humans
Evolution of Hominids
Evolution of Humans
Picture Reference

Origin of Life

Chemical Evolution

Data suggest that a chemical evolution produced the first cell.
Every living thing comes from cells and every cell comes from a preexisting cell.
Chemical evolution may have produced the first cell.
The Primitive Earth

o The planets, the sun, and the earth formed 10 billions years ago.

o The earth’s mass has a gravitational field that it is strong enough to have an atmosphere.

o Using an outside energy source, small organic molecules were produced by reactions between early earth’s atmospheric gases.

Small Organic Molecules

o Stanely Miller’s experiment suggested that the gases of early earth could have become the first organic molecules.

Stanely Miller’s experiment

Macromolecules

o Macromolecules evolved and interacted.

o The RNA first hypothesis-only macromolecule RNA was needed for the first cell(s).

o The protein first hypothesis-amino acids join to form polypeptides when exposed to dry heat.

The Protocell

o A cell has a lipid-protein membrane.

o The protocell, a heterotrophic fermenter, lived on preformed organic molecules in the ocean.

The True Cell

o The protocell eventually became a true cell once it had genes composed of DNA and could reproduce.

Biological Evolution

The first true cell were the simplest of life forms.

o A prokaryotic cell, which lack a nucleus.

o Later the eukaryotic cell, which has nuclei, evolved.

o Then multicellularity and other kingdoms developed.

o Biological evolution is the process by which a species changes through time.

§ Has two important aspects

v Descent from a common ancestor explains the unity of living things.

v Adaptation to the different environments explains the great diversity of living things.

Common Descent

o Fossils are the best evidence for evolution because they are the actual remains of species that lived on earth at least 10,000 years ago and up to billions of years ago.

o Fossils can be the traces of past life or and other direct evidence that past life existed.

o The fossil record is the history of life recorded by fossils, and paleontology is the science of discovering the fossil record and, from it, making decisions about the history of life, ancient climates, and environments.

Fossils

o Biogeography is the study of the distribution of plants and animals in different places throughout the world.

o Anatomical evidence-the common anatomies and development of a group of organisms are explainable by descent from a common ancestor.

o Biochemical evidence- all organisms have similar biochemical molecules.

Natural selection

o Natural selection is a population adapted to its local environment.

o Example: that giraffe’s necks are long because they’re food was high in the trees and they adapted.

Classification of Humans

The binominal name of an organism gives its genus and species.
Classification of humans can be used to trace their ancestry.
Humans are primates.

o Primates are adapted to an orboreal life.

o Primate limbs are mobile and hands and feet both have five digits each.

o Primates have binocular vision.

o Have large and complex brain.

o Primates have on birth at a time.

Comparing Human Skeleton to the Chimpanzee Skeleton

o Human and chimpanzee are 99% identical the difference is in various genes.

o A primate evolutionary three shows that humans share a common ancestor with African apes.

Evolution of Hominids

Evolution of Primates

The first hominids most likely lived about 6-7 MYA. ( including Humans)
The First Hominids

o Hominid is a term that refers to our branch of the evolutionary tree.

o Lineage is evolutionary line of descent.

o Molecular clock- mutational changes that accumulate at a presumed constant rate in regions of DNA not involved in adaptation to the environment.

Hominid Features

o Bipedal posture walking on two feet.

o Shape of face- humans has a flatter face and more pronounced chin than apes do because humans have shorter jaws.

o Size of brain- chimpanzee have a brain size of 400 cm^3 and human have 1,300 cm^3.

Earliest Fossil Hominids

o Sahelanthropus tschadensis, dated at 7 MYA, was found by Chad, located in central Africa.

o Orrorin tugenensis, dated at 6 MYA and found in eastern Africa, the early hominide because the limb anatomy suggests a bipedal posture.

o Ardipithecus kadabba, found in eastern Africa and dated 5.8 and 5.2 MYA, is closely related to the later appearing Ardiphithecus ramidus.

Evolution of Australopithecines

o The hominid line of descent begins to earnest with the australopithecines, a group of species that evolved and diversified in Africa.

o Ardipithecines were most likely hominids.

o The evolutionary tree of hominids resembles a bush (not a straight line of fossils leading to modern humans).

o Australopithecines (a hominid) lived about 3 MYA.

o They could walk erect, but they had a small brain.

o This testifies to a mosaic evolution for humans (not all advanced features evolved at the same time).

Evolution of Humans

Early Homo

o Fossils are classified as Homo with regard to brain size (over 600cm^3) jaws and teeth (resemble modern humans’) and evidence of tool use.

o Culture, which encompasses human behavior and products, depends upon the capacity to speak and transmit knowledge.

o H. habilis made and used tools and is known to have a culture first.

o H. erectus was the first Homo to have a brain size of more than 1,000 cm^3.

o H. erectus mirgrated from Africa into Europe and Asia.

o H. erectus used fire and may have been big-game hunters.

Evolution of Modern Humans

Human Evolution

o Homo sapiens (modern humans).

o The hypothesis that Homo sapiens evolved in several different locations is called the multiregional continuity hypothesis. (Europe, Africa and Asia).

o The out-of-Africa hypothesis, which proposes that H. sapiens evolved from H. erectus only in Africa, and thereafter H. sapiens migrated to Europe and Asia about 100,000 year BP (before present).

Neandertals

o The neandertals were already living in Europe and Asia before modern human arrived.

o They had a culture, but did not have the physical traits of modern humans.

o Lived in caves. They used and could control fire.

o They even buried their dead with flowers and tools, may have been capable to thinking symbolically.

Neandertal families

Cro-Magnons

o Cro-Magnons are the oldest fossil to be designated H. sapiens.

§ Their tools were sophisticated and they had a culture.

o Cro-Magnons seen to have replaced neandertals in the Middle East and then spread to Europe.

o May have been the first to have a language.

o Culture included art, paintings they did in caves (located in Spain and France).

Cro-Magnons

Picture Reference

§ Chemical evolution, Human Biology, page 468.

§ Stanely Miller’s Experiment

o http://www.kennislink.nl/upload/150080_962_1144771463083-oersoepexperimentMiller.jpg

§ Fossils, Human Biology, page 470

§ Evolution of Primates, Human biology, page 478

§ Human Evolution, Human biology, page 481

§ Neandertals, http://acacia.cnice.mecd.es/~jgaf0010/im%E1genes/neandertal-familia.jpg

§ Cro-Magnons, http://www.astrosurf.com/luxorion/Bio/cro-magnon-caverne.jpg

Chapter 23

Global Ecology and Human Interferences

Table of Concepts

The Nature of Ecosystems
Energy Flow
Global Biogeochemical Cycles
Picture References

The Nature of Ecosystems

The Major Terrestrail Ecosystems

The biosphere is where organisms are found on planet Earth, from the atmosphere above to the depths of the oceans below and everything in between.
The entire biosphere is one giant ecosystem, a place where organisms interact among themselves and with the physical and chemical environment.
Humans can alter the interaction between organisms and change the ecosystem.
Ecosystems

o Scientists recognize several distinctive major types of terrestrial ecosystems, also called biomes.

o Temperature and rainfalls define the biomes, which contain communities of organisms adapted to the regional climate the tropical rain forest, which occurs at the equator, is dominated by large evergreen, broad-leaved trees.

o Terrestrial ecosystems are forest (tropical rain forests, coniferous, temperate deciduous), grassland (savanna and prairie), and deserts, which includes the tundra.

o Aquatic ecosystems are either salt water (seashores, oceans, coral reefs, estuaries) or freshwater (lakes, ponds, rivers, and streams).

o The ocean is a marine ecosystem that covers 70% of the earth’s surface.

Biotic Components of an Ecosystem

o The abiotic components of an ecosystem are the nonliving components.

o The biotic components are living things that can be categorized according to their food source.

o Autotrophs require only inorganic nutrients and an outside energy source to produce organic nutrients for their own use and for all the other members of a community. They are called producers-they produce food.

o Heterotrophs need a source of organic nutrients. They are the consumers-they consume food. Herbivores are animals that graze directly on plants or algae.

o Carnivores feed on other animals; birds that feed on insects are carnivores.

o Omnivores are animals that feed both on plants and animals. Humans are omnivores.

o Detritus feeders are organisms that feed on detritus, which is decomposing particles of organic matter. (Marine fan worms, earthworms, some beetles, termites and ants).

o Decomposers feed on detritus, releasing inorganic substances back into the ecosystem.

o Niche is the role of an organism in an ecosystem: how it gets its food and what eats it, and how it interacts with other populations in the same community.

o In a community, each populations has a habitat (residence) and a niche (its role in the community).

Energy Flow and Chemical Cycling

Energy Flow

o Energy flow and chemical cycling characterize ecosystems.

o Energy flow through the populations of an ecosystem.

o Chemical cycle within and among ecosystems.

Energy Flow

Food Web

Various interconnecting paths of energy flow are called a food web.
A food web is a diagram showing how various organisms are connected by eating relationships.
Grazing food webs begin with vegetation eaten by an herbivore that becomes food for a carnivore.
Detrital food webs begin with detritus, food for decomposers and for detritivores.
Members of detrital food webs can be eaten by aboveground carnivores, joining the two food webs.
Trophic Levels

o Diagrams that show a single path of energy flow are called food chains.

o A trophic level is composed of all the organisms that feed at a particular link in a food chain.

Ecological Pyramids

o The flow of energy with large losses between successive trophic levels is sometimes depicted as an ecological pyramid.

o Pyramids of biomass eliminate size as a factor because biomass is the number of organisms multiplied by the weights of organic matter within one organism.

o Ecological pyramids illustrate that biomass and energy content decrease from on trophic level to the next because of energy loss.

Global Biogeochemical Cycles

The pathways by which chemicals circulate through ecosystems involve both living (biotic) and nonliving (geological) components; therefore, they are known as biogeochemical cycles.

o Can be gaseous or sedimentary.

Have reservoirs that contain inorganic nutrients available to living things on a limited basis.
Exchange pools are sources of inorganic nutrients.
Nutrients cycle among the biotic communities (producers, consumers, decomposers) of an ecosystem.
The Water Cycle

The Water Cycle

o The reservoir of the water cycle is freshwater that evaporates from the ocean.

o Water that falls on land enters the ground, surface waters, or aquifers and evaporates again.

o All water returns to the ocean.

o During evaporation in the water cycle, the sun’s rays cause freshwater to evaporate from seawater, and the salt are left behind.

o Vaporized freshwater rises into the atmosphere, condenses, and then falls as precipitation (rain, snow, hail) over the oceans and the land.

o Runoff is water that flows directly into nearby streams, lakes, wetlands or the ocean.

o Humans interfere with the water cycle in three ways:

§ They withdraw water from aquifers

§ They clear vegetable from land and build road and buildings that prevent percolation and increase runoff

§ They interfere with the natural processes that purify water and instead add pollutants like sewage and chemicals to water.

The Carbon Cycle

The Carbon Cycle

o The carbon dioxide (CO2) in the atmosphere is the exchange pool for the carbon cycle.

o The reservoirs of the carbon cycle are organic matter (forests and dead organisms for fossils fuels), limestone, and the ocean (calcium carbonate shells).

o The exchange pool is the atmosphere

o Photosynthesis removes carbon dioxide from the atmosphere.

o Respiration and combustion add carbon dioxide to the atmosphere.

o Greenhouse gases are contributing significantly to an overall rise in the Earth’s ambient temperature, a phenomenon called global warming because of the greenhouse effect.

The Nitrogen Cycle

Nitrogen Cycle

o Nitrogen gas makes up about 78% of the atmosphere, but plants cannot make use of nitrogen gas.

o The reservoir of the nitrogen cycle is the atmosphere.

o Nitrogen gas must be converted to a form usable by plants (producers).

o Nitrogen-fixing bacteria (in root nodules) convert nitrogen gas to ammonium, to form producers can use.

o Nitrifying bacteria convert ammonium to nitrate.

o Denitrifying bacteria convert nitrate back to nitrogen gas.

The Phosphorus Cycle

The Phosphorus Cycle

o The reservoir of the phosphorus cycle is ocean sediments.

o Phosphate is ocean sediment becomes available through geological upheaval, which exposes sedimentary rocks to weathering.

o Weathering slowly makes phosphate available to the biotic community.

o Phosphate is a limiting nutrient in ecosystems.

Picture References

The Major Terrestrail Ecosystems, Human Biology, page 492
Energy-Flow, http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/ecosystem/zebra2.gif
Food Web, http://tli.jefferson.k12.ky.us/stlp/05Camp/Layne/Images/Food%20Web.jpg
The Water Cycle, http://en.wikivisual.com/images/9/94/Water_cycle.png
The Carbon Cycle, http://www.powledge-words.net/AbtBdx/Assets/Images/carbon_cycle_diagram.gif
Nitrogen Cycle, http://www.enviroliteracy.org/images/page-spec/nitrogen_cycle.gif
The Phosphorus Cycle, http://www.enviroliteracy.org/images/page-spec/nitrogen_cycle.gif

Chapter 24

Human Population, Planetary Resources, and Conservation

Table of Concepts

Human Population Growth
Human Use of Resources and Pollution
Biodiversity
Working Toward a Sustainable Society
Picture References

Human Population Growth

World Population Growth

Populations have a biotic potential for increase in size.
The growth rate of a population is determined by considering the difference between the number of persons born per year and the number who die per year.
Biotic potential is normally held in check by environmental resistance.
Population size usually levels off at carrying capacity.
The MDCs Versus the LDCs

o More-developed countries (MDCs) typified by countries in North America and Europe, are those in which population growth is modest and the people enjoy a good standard of living.

o Less-developed countries (LDCs) typified by some countries in Asia, Africa, and Latin America, are those in which population growth is dramatic and the majority of people live in poverty.

o MDCs did not always have low population increases.

§ The MDCs have a 0.1% growth rate since 1950.

§ MDCs are approaching a stable population size.

o LDCs growth rate is presently 1.6% after peaking at 2.5% in the 1960s.

§ Age-structure diagrams can be used to predict population growth.

§ LDC populations will continue to increase in size.

Age Structure Diagrams

Human Use of Resources and Pollution

Five resources are maximally used by humans:

o Land

o Water

o Food

o Energy

o Minerals

Resources are either nonrenewable or renewable.
Nonrenewable resources are not replenished and are limited in quantity.
Renewable resources are replenished but still are limited in quantity.
Land

o Human activities, such as habitation, farming, and mining, contribute to erosion, pollution, desertification, deforestation, and loss of biodiversity.

Water

o Industry and agriculture use most of the freshwater supply. Water supplies are increased by damming rivers and drawing from aquifers. As aquifers are depleted, subsidence, sinkhole formation, and saltwater intrusion can occur. If used by industries, water conservation methods could cut world water consumption by half.

Food

o Food comes from growing crops, raising animals, and fishing.

o Modern farming methods increase the food supply, but some methods harm the land, pollute water, and consume fossil fuels excessively.

o Genetically engineered plants increase the food supply and reduce the needs for chemicals.

o Raising livestock contributes to water pollution and uses fossil fuel energy.

o The increased number and high efficiency of fishing boats have caused the world fish catch to decline.

Energy

o Fossil fuel are nonrenewable sources. Burning fossil fuels and burning to clear land for farming cause pollutants and gases to enter the air.

o Greenhouse gases include CO2 (carbon dioxide) and other gases. Greenhouse gases cause global warming because solar radiation can pass through, but infrared heat cannot escape back into space.

o Renewable resources include hydropower, geothermal, wind, and solar power.

Minerals

o Minerals are nonrenewable resources that can be mined.

§ Include: sand, gravel, phosphate, and metals.

o Mining causes destruction of the land by erosion, loss of vegetation, and toxic runoff into bodies of water.

o Some metals are dangerous to health. Land ruined by mining can take years to recover.

o Heavy metals (lead, arsenic)

o Ozone shield destruction is associated with CFCs.

o Other synthetic organic chemicals enter the aquatic food chain, where the toxins become more concentrated (biological magnification).

Biodiversity

Biodiversity is the variety of life on Earth. The five major causes of biodiversity loss and extinction are:

o Habitat loss

Habitat loss

o Introduction of alien species

o Pollution

o Overexploitation of plant and animals

o Disease

Direct Value of Biodiversity

o Direct values of biodiversity are:

§ Medicinal value (medicines derived from living organisms)

§ Agricultural value

§ Consumptive use values (food production).

Indirect Value of Biodiversity

o Biodiversity in ecosystems contributes to:

§ Waste disposal

§ Freshwater provision through the water biogeochemical cycle

§ Prevention of soil erosion, which occurs naturally in intact ecosystems

§ Function of biogeochemical cycles

§ Climate regulation (plants take up carbon dioxide)

§ Ecotourism (human enjoyment of a beautiful ecosystem).

Working Toward a Sustainable Society

A sustainable society would always be able to provide the same amount of goods and services for future generations, as it does at present.
A sustainable society would use only renewable energy sources, would reuse heat and waste materials, and would recycle almost everything. It would also provide the same goods and services presently provided and would preserve biodiversity.

Learning to Recycle

Picture References

EMBRONIC AND FETAL DEVELOPMENT

2008-05-09T21:09:00.000-07:00

This lab project is about the fetus development. What’s an important week during a fetus development and why.

Week Two

This image is about implantation. It is an important stage of pregnancy because this is where it starts. When fertilization takes place the sperm and egg form a zygote. This stage is the beginning of pregnancy often around day 14 of a 28-day cycle, when a woman ovulates. The gender is also determined in the beginning. I find this to be a very important stage because it’s a beginning of life for a new person; it is when a man and women become parents. The second week is when the embryo implant itself to the uterus, when implantation is successful the women is clinically pregnant.

Week three

The third week is important because important organ systems are making their appearances. The nervous system is the first organ system to be visible. Also week three is the development of the heart. HCG (human chorionic gonadotropin) is significant because it tells the ovaries to stop releasing eggs and to increase production of estrogen and progesterone. HCG is also useful to home pregnancy test it detects pregnancy. I find this very important because this is when a woman finds out she is pregnant.

Week Four

At week four, all of the baby’s organs are developing will some will begin to function. A baby is most vulnerable at this stage (week four to week ten) with his or her development, it can have some interferes. The amniotic sac is also present, it surrounds the baby while he or she grows. I find this stage very important because the baby is vulnerable and drugs or alcohol can affect the baby’s development. Drugs or alcohol can lead to miscarriage also.

Week Five

Week five is when the heart starts beating. The umbilical cord also develops which is the baby’s lifeline. The umbilical cord’s responsibility is to pump oxygen, remove waste and supply nutrients to the baby throughout the pregnancy. The lungs also develop along with the brain. The arm and legs start appear like buds. I find week five important because the he or she heart starts to beat!!

Week Ten

Week ten the baby is now called a fetus because most of the baby’s development is complete it is also the end of embryonic development and time for fetal development. Fingernails also appear. The eyelids are still closed but the eye color has already developed. Week ten is an important stage because the baby is now identified as a fetus.

Week Fourteen

Week fourteen is also the second trimester for the mother and her baby. The brain impulses and the facial muscles are getting a workout because the fetus is making expressions. The kidney are also producing urine with is release into the amniotic fluid. The fetus is also making some movements and may even be felt! This week is important because the fetus is out of harm way and the fetus and mother are in the second trimester. The gender can also be detected with ultrasound and his or her bones are getting stronger.

Week twenty-three

Week 23 (around 6 months) the fetus moves around even more! The fetus eye’s can open and close and react to light, some baby can see through their mother’s belly with really bright lights. Also the vocal cords are developing. Blood vessels are also developing in the lungs to help him/her to breathe. The fetus also can hear from inside the womb. I found that this was an important week/month because the unborn baby has developed their senses of hearing which means that the baby’s brain has developed even more.

Week twenty-Eight

Week 28 (7 months) the fetus is starting to grow hair, eyelashes and eyebrows. The little baby’s skin is pink and smooth. The fetus’s brain is growing dramatically each week and will continue after the baby is born and years to come. The lungs are still developing but aren’t fully developed just yet but if born prematurely the baby has a good chance of survival. The baby is also developing billions of neurons in their brain and also gaining more weight and getting longer. I found this to be an interesting week because the baby is growing hair already and also the brain is still developing rapidly and if he or she was born now it has a chance of survival.

Week Third-Four

Week 34 or around week 8. The fetus is gaining ½ ounce a day, looking less wrinkled, their fat is filling in and is very crammed up in their mother’s stomach now. The fetus fat layers will help regulate their body temperature once he or she is born. The fetus’s central nervous system (CNS) is maturing and the lungs are still completing to mature. Babies that are born between 34-37 weeks well have no real health problems and will be born healthy. I found this to be a important week because even if the baby has a chance of survival if born the lungs can still not be matured yet, so it is very important to keep the baby inside of the womb until the actually due date.

Week 40

Week 40 or month 9. The fetus is ready to be born. The fetus is officially considered “full term”. The fetus will position its head downward to their mother’s bony pelvis. The umbilical cord is over 2 feet in length and the placenta weighs about a pound and ½. The fetus’s skull bone is not yet complex which allows the head to fit through the birth canal during labor. The fetus now a baby is ready to be born.

Conclusion:
This was a great lab!! I learned a lot. I am a mother of a four year old. I had him at 32 weeks and had to spend 2 weeks in the hospital because his lungs were not yet developed yet. But he wouldn’t wait and I had him but his lungs were developed and he was a healthy boy. I learned a lot about what a fetus goes through the first 9 months being in the womb and now important it is to keep the baby healthy and his or her mother.

Reference:
www.babycenter.com

What to expect when you’re expecting, H. Murkoff, A. Eisnberg, S. Hathaway, 2002

Human Biology, S. Mader, 2008.

Chapter 16 & 17

2008-05-09T20:29:00.000-07:00

Chapter 16

Reproductive System

Chapter Concepts

Human life Cycle
Male Reproductive System
Female Reproductive System
Female Hormone Levels
Control of Reproduction
Sexually Transmitted Diseases
Picture References

Human life Cycle

The reproductive system is quite different in male and females. Puberty is the sequence of events by which a child becomes a sexually competent young adult.
Does not begin fully until puberty is complete. Sexual maturity occurs between the age of 11-13 in girls, and 14-16 in boys. At the completion of puberty both boys and girls are capable of producing children.
Mitosis and Meiosis

o The two type of cell division in the human life cycle are mitosis and meiosis. Mitosis is duplication division (number of chromosomes stays the same). Mitosis is the type of cell division that takes place during growth and repair of tissues. Meiosis is reduction division (number of chromosomes is reduced).

o The mother chromosomes contribute 23 to the new individual and the father also contributes 23.

o Meiosis occurs in the male’s testes and females ovaries.

Mitosis and Development

Male Reproductive System

The external genitals of males are:

o The penis (organ of sexual intercourse)

o The scrotum (contains the testes)

Sperm produced by the testes mature within the epididymis, which is a tightly coiled duct laying just outside each testis.
When sperm leave an epididymis they enter a vas deferens also called the ductus deferens, where they may also be stored for a time. It is where mature sperm are stored.
The ejaculation ducts enter the urethra.
When sperm leaves the penis in a fluid its called semen.

The Male Reproductive System

Orgasm in Males

o The penis is the male organ of sexual intercourse.

§ Circumcision, the surgical removal of the foreskin, is usually done soon after birth.

o During sexual arousal, autonomic nerves release nitric oxide, NO.

o Stimulus leads to the production of cGMP which causes the smooth muscle of incoming arterial walls to relax and the erectile tissue to fill with blood.

o The veins that take blood away from the penis are compressed, and the penis becomes erect.

o Erectile dysfunction exists when the erectile tissue doesn’t expand enough to compress the veins.

Male Gonads, the Testes
The testes, which produce sperm.
The testes begin their development inside the abdominal cavity but descend into the scrotal sacs during the last two months of fetal development.
Spermatogenesis, occurring in seminiferous tubules of the testes, produces sperm.
Mature sperm have three distinct parts:

o Head, middle piece and a tail.

Mitochondria in the middle piece provide energy for the movement of the tail, which is a flagellum.
The head contains a nucleus covered by a cap called the acrosome, which stores enzymes needed to penetrate the egg.
A normal human male contains several hundred million sperm but only one sperm enters an egg.
Does not usually live more than 48 hours in the female genital tract.
Cells that lie between the seminiferous tubules secrete the male sex hormones, the androgens they are called interstitial cells.

Testis and Sperm

Hormonal Regulation in Males

o The hypothalamus has ultimate control of the testes’ sexual function because it secretes a hormone called gonadotropinreleasing hormone (GnRH) that simulates the anterior pituitary to secrete the GnRH.

o Testosterone, the main sex hormones in males are essential for the normal development and functioning of the organs.

o Hormonal regulation, involving secretions from the hypothalamus, the anterior pituitary, and the testes, maintains a fairly constant level of testosterone.

o FSH from the anterior pituitary promotes spermatogenesis.

o LH from the anterior pituitary promotes testosterone production by interstitial cells.

Female Reproductive System

The female gonads are paired ovaries that lie in shallow depressions, one on each side of the upper pelvic cavity.
The ovaries produce eggs and the female sex hormones, estrogen and progesterone.
The Genital Tract

o Oviducts, also called the uterine or fallopian tubes extend from the uterus to the ovaries.

o Zygote diploid cell formed by the union of sperm and egg; the product of fertilization.

o Implantation the embryo embeds in the uterine lining

The Female Reproductive System

o The cervix contains opening to uterus

o Development of the embryo and fetus normally takes place in the uterus.

o The vagina is the organ of sexual intercourse and the birth canal in females.

Orgasm in Females

o Orgasm is female culminates in uterine and oviduct contractions.

o Orgasm occurs at the height of the sexual response.

Female Hormone Levels

Ovarian Cycle: Non-pregnant

o An ovary contains many follicles, and each one contains an immature egg, called an oocyte.

o A female is born with as many as two million follicles but is reduced to 300,000-400,000 by the time of puberty.

o A woman produces only one egg per money during her reproductive years.

o As the follicle matures during the ovarian cycle, it changes from a primary to a secondary to a vesicular follicle.

o Oogenesis is a production of an egg in females by the process of meiosis and maturation.

o Ovulation is a release of a secondary oocyte from the ovary; if fertilization occurs, the secondary oocyte becomes an egg.

o The corpus luterum secretes progesterone and some estrogen.

Ovarian Cycle

· Estrogen and Progesterone

o Affect not only the uterus but other parts of the body as well.

o Estrogen is responsible for sex characteristics in females (body hair and fat distribution).

§ Females are more rounded than male

o The development to produce milk following pregnancy.

o Menopause, the period in a woman’s life during which the ovarian cycle ceases, likely occurs between ages 45-55.

§ Menstruation becomes irregular.

§ Completed menopause until menstruation is absent for a year.

· Uterine Cycle: Non-pregnant

o The female sex hormones, estrogen and progesterone, have numerous functions.

o Uterine cycle is monthly occurring changes in the characteristics of the uterine lining (endometrium).

o 28 day cycle are divided:

§ Days 1-5, a low level of estrogen and progesterone. Day one of the cycle, a flow of blood and tissues, known as the menses, passes out of the vagina during menstruation.

§ Days 6-13, increased production of estrogen by a new ovarian follicle in the ovary causes the endometrium to thicken and become vascular and glandular. This cycle is called the proliferative phase.

§ Day 14, ovulation occurs.

§ Days 15-28, increased production of progesterone by the corpus luterum in the ovary causes the endometrium of the uterus to double or triple in thickness and the uterine glands to mature. This is called the sercetory phase.

Female Hormone Levels

· Fertilization and Pregnancy

o During unprotected sexual intercourse, sperm will likely reach the egg located following ovulation.

o Only one sperm fertilizes an egg and then it becomes a zygote.

o The placenta, which sustains the developing embryo and later the fetus, starts from both maternal and fetal tissues.

o The embryo implants itself in the thickened endometrium.

o The placenta produces HCG (human choronic gonadotropin), which maintains the corpus luterum in the ovary.

§ A pregnancy test detects HCG

o Menstruation does not occur during pregnancy (a skipped period is a sign of pregnancy).

· Birth control pill is a way to not get pregnant.

· Birth control pill thicken the cervical mucus, preventing sperm to enter the uterus.

· When taking birth control pills the hormones that are in the pill feedback to inhibit the hypothalamus and the anterior pituitary; so no new follicles begin in the ovary.

Control of Reproduction

· Birth control methods are used to regulate the number of children an individual or couple will have.

· Birth Control Methods

Birth Control devices

o The most reliable method of birth control is ABSTINENCE

o Contraceptives are medications and devices that reduce the chance of pregnancy.

§ IUD (intrauterine device) – a small piece of molded plastic that is inserted into the uterus.

§ Diaphragm- is a soft latex cup with a flexible rim that lodges behind the pubic bone and fits over the cervix.

§ Female condom- consists of a large polyurethane tube with a flexible rind that fits onto the cervix.

§ Male condom- is most often a latex sheath that fits over the erect penis.

§ Contraceptive implants- utilizes synthetic progesterone to prevent ovulation by disrupting the ovarian cycle.

§ Contraceptive injections- are available as progesterone only or a combination of estrogen and progesterone. Each injection can vary from three to a few weeks.

§ Contraceptive vaccines- are now being developed. A vaccine intended to immunize women against HCG, the hormone so necessary to maintaining the implantation of the embryo.

§ Vasectomy- consists of cutting and sealing the vas deferen on each side so that the sperm are unable to reach the seminal fluid that is ejected at the time of orgasm.

§ Tubal ligation- consists of cutting and sealing the oviducts. Pregnancy rarely occurs because the passage of the egg through the oviducts has been blocked.

· It is view a vasectomy and tubal ligation as permanent.

· Even following successful reconnection, fertility is usually reduced by about 50%.

§ Morning after pill, or emergency contraception, is a medication that will prevent pregnancy after unprotected intercourse.

· Infertility

· Infertility is a failure of a couple to achieve pregnancy after one year of regular, unprotected intercourse.

· Cause of infertility:

o Cause in male is low sperm count or a large amount of abnormal sperm. Abnormal sperm can be due to environmental influences:

§ Alcohol

§ Smoking

§ Sitting around at computer or driving, the testes temperature remains too high for adequate sperm production.

o Body weight in women appears to be the most significant factor in causing female infertility.

o Sometime medication can correct infertility.

· Assisted reproductive technologies

· Artificial insemination by donor (AID)- during artificial insemination, sperm is placed in the vagina by a physician. If partner has a low sperm count it is collected till it can be implanted.

· In vitro fertilization (IVF)- conception occurs in laboratory glassware. About two or three days the embryo is implanted in the women’s uterus that is in the secretory phase of her uterine cycle.

· Gamete intrafallopian transfer (GIFT)- the term gamete refers to a sex cell, either a sperm or an egg. Used the same way as IVF but are placed immediately.

· Surrogate mother- woman are contracted and paid to have babies. The contracting parents can contribute the sperm and even the egg.

· Intracytoplasmic sperm injection (ICSI)- a single sperm is injected into an egg. It is used when a man has severe infertility problems.

Sexually Transmitted Diseases

· Sexual transmitted disease (STDs) is caused by viruses, bacteria, protests, fungi, and animals.

· STDs Caused by Viruses

o AIDs is caused by HIV (human immunodeficiency virus). It is the last stage of HIV.

§ The primary host for HIV is a helper T lymphocyte.

§ There are no cures for AIDS but there are treatments. It helps stop HIV reproduction but treatment has to be taken indefinitely or the virus will rebound.

o Genital warts are caused by human papillomaviruses; these viruses cause warts or lesions on genitals and are associated with certain cancers.

§ Many times people don’t show signs of warts.

§ Can have the warts removed by surgery but may recur.

§ There are new vaccine that is important because genital warts can lead to cancer.

§ Researchers believe that these viruses can be involved in 90% of cancer of the cervix.

o Genital herpes is caused by herpes simplex virus type 2; causes blisters on genitals.

§ Some people show no symptoms to the virus.

§ Some people experience blisters on the genitals and is very painful and takes days to heal.

Genital Herpes around the mouth

o Viruses A, B, C, D, E, and G cause hepatitis. A and E are usually acquitted from contaminated water; hepatitis B and C from blood borne transmission; and B, D, and G are sexually transmitted.

o Hepatitis infects the liver and can lead to liver failure, liver cancer and death.

· STDs Caused by Bacteria

o Only STDs caused by bacteria are curable with antibiotics.

o Chlamydia is caused by Chlamydia trachomatis; PID can results.

§ The incidence of new Chlamydia infections has steadily increased since 1984.

§ The infections of the lower reproductive tract are usually mild especially in women.

§ Men may experiences burning sensation on urination and a muciod discharge.

§ Causes cervical ulcerations, which increase the risk of acquiring HIV.

o Gonorrhea is caused by the bacterium, neisseria gonorrhoeae.

§ Gonorrhea can spread to internal parts of the body, causing heart damage or arthritis.

§ Gonorrhea was curable by antibiotic therapy but resistance to antibiotic is becoming more and more common, and 40% of all strains are now known to be resistant to therapy.

o Syphilis is caused by a bacterium called treponema pallidum.

§ Penicillin is an effective antibiotic.

§ Has three stages:

· Primary stage-indicated the site of infection

· Secondary stage- breaks out in a rash that does not itch and seen on hands and feet.

· Tertiary stage-syphilis many affect the cardiovascular system by causing aneurysms, particularly in the aorta. This stage can result to death.

Syphillis

· Two Other Infections

o Bacterial vaginosis is caused by gardneralla vaginalis.

§ Believed to be accounted for 50% of vaginitis case in American women.

o Trichomoniasis is an overgrowth of Candida albicans.

§ Is a normal organism found in the vagina; its growth simply increases beyond normal under certain circumstances.

7. Picture References:

http://fig.cox.miami.edu/~cmallery/150/mitosis/lifecycle.jpg

http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f28-11_male_pelvic_regi_c.jpg

http://fig.cox.miami.edu/~cmallery/150/devel/c7.46.12.spermatogenesis.jpg

http://academic.kellogg.cc.mi.us/herbrandsonc/bio201%5FMcKinley/f28-2_sagittal_section__c.jpg

http://www.lib.mcg.edu/edu/eshuphysio/program/section5/5ch9/5ch9img/page3.jpg

http://baby4you.co.nz/images/Resized_Menstural_Cycle_for.gif

http://www.herpes-doctor.com/image_files/herpesmouth.jpg

http://www.aidsmeds.com/images/syphilissore.jpg

Chapter 17

Development and Aging

Chapter Concepts

1. Fertilization

2. Pre-Embryonic and Embryonic Development

3. Fetal Development

4. Pregnancy and Birth

5. Development After Birth

6. Picture References

1. Fertilization

· Fertilization is the union of a sperm and egg to form zygotes, the first cell of the new individual.

· Steps of Fertilization

o The tale of the sperm is a flagellum, which allows it to swim to the egg.

o Fertilization occurs when a sperm makes it way through the corona radiata, acrosome releases digestive enzymes to digest zona pellucida, sperm binds to the egg, their plasma membranes fuse, sperm enters the egg, and egg and sperm nuclei fuse.

Fertilization

2. Pre-Embryonic and Embryonic Development

· Processes of Development

o Cleavage- the zygote begins to divide so that there are first 2, then 4, 8, 16, and 32 cells, and so forth. Cell division during cleavage is mitotic, and each cell receives a full complement of chromosomes and genes.

o Growth- during embryonic development, cell division is accompanied by an increase in size of the daughter cells.

o Morphogenesis- Refers to the shaping of the embryo and is first evident when certain cells are seen to move, or migrate, in relation to other cells. The embryo begins to assume various shapes.

o Differentiation- when cells take on a specific structure and function, differentiation occurs. The first system to become visibly differentiated is the nervous system.

· Extra embryonic Membranes

o The extra embryonic membranes are not part of the embryo and fetus; but instead are outside of the embryo.

o Develop inside of the uterus.

§ Functions:

· Chorion- develops into the fetal half of the placenta, the organ that provides the embryo/fetus with nourishment and oxygen and takes away its waste. Blood vessels within the chorionic villi are continuous with the umbilical blood vessels.

· Allantois- like a yolk sac extends away from the embryo. It collects the small amount of urine produced by the fetal kidneys and later gives rise to the urinary bladder.

· Yolk sac- the yolk sac is the first embryonic membrane to appear. Contains plentiful blood vessels. It’s the first site of blood cell formation.

· Amnion- enlarges as the embryo and then the fetus enlarges. It contains fluid to cushion and protect the embryo, which develops into a fetus.

Human Embryonic Development

· Stages of Development

o The 280 days is called the normal gestation period.

o Only 5% of babies actually arrive on the predicted date.

o Pre-embryonic development encompasses the events of the first week.

o A morula is a compact ball of embryonic cells that becomes a blastocyst.

o The many cells of the blastocyst arrange themselves so that there is an inner cell mass surrounded by an outer later of cells.

o The inner cell mass will become the embryo, the layer of cells will become the chorion.

o Embryonic development begins with the second week and last until the end of the second month of development.

§ Second week-

· the embryo usually begins the process of implanting itself in the wall of the uterus.

· When implantation is successful, the women are clinically pregnant.

· If the embryo implants itself other location that is not the uterus it is called ectopic pregnancy.

· The chorion beings HCG. Pregnancy test detects HCG.

§ Third week-

· Two important organ system makes their appearance during the third week. The nervous system is the first organ.

· Development of the heart begins

§ Fourth and fifth weeks-

· A body stalk connects the embryo to the chorion which has treelike projections called chorionic villi.

· The umbilical cord, connects the developing embryo to the placenta is fully formed.

§ Sixth through eighth weeks-

· The embryo changes to a form that is recognized as a human being.

· Embryo is 38 mm (1.5 in).

An Embryo and three primary germ layers

3. Fetal Development

· At the end of the embryonic period, all organ systems are established, and there is a mature and functioning placenta. The umbilical arteries and umbilical vein takes blood to and from the placenta, where exchanges take place.

· Exchanges supply the fetus with oxygen and nutrients and rid the fetus of carbon dioxide and wastes.

· The umbilical cord is the lifeline of the fetus because it contains the umbilical arteries and vein.

· The venous ducts join the umbilical vein to the inferior vena cava.

Fetal circulation

· Events of Fetal Development

o Fetal development includes the third through the ninth months of development.

o Third and fourth months

§ Cartilage begins to be replaced by bone as ossification centers appear in most of the bones.

§ The skull has six large membrane areas called fontanels.

§ It is possible to determine the sex of the baby, boy or girl. The SRY gene is presence, usually on the Y-chromosomes.

§ The heartbeat is loud enough to be heard by a stethoscope.

§ The fetus is 152mm (6 in). Weighs (6 oz).

o Fifth through seventh months

§ A month can feel movement

§ A fine down called lanugo covers the wrinkled, translucent skin.

§ A white, greasy, cheese like substance called vernix caseosa.

§ The eyelids are now fully open.

§ The fetus is 300mm (12 in.) and weighs (3 lb)

o Eighth through Ninth Months

§ End of the nine month the fetus is 530mm (20 ½ in.) weighs (7 ½ lb.)

§ Full term babies have a best chance of survival while premature births chances are lower.

§ The end of development the fetus points its head toward the cervix.

§ If the fetus does not turn a breech birth will happen.

§ A cesarean section or c-section may be delivery of the fetus.

· Development of Male and Female Genitals

Female and Male external genitals

o The sex of an individual is determined at the moment of fertilization.

o At six weeks a small bud appears either the male penis or female clitoris

o Nine weeks, a urogenital groove bordered by two swellings appears.

o Fourteen week, the groove disappears, the swelling goes down and the male or female genital take form.

4. Pregnancy and Birth

· Major changes take place in the mother’s body during pregnancy.

· Weight gain occurs as the uterus occupies most of the abdominal cavity.

· Birth

o The uterus had contractions throughout pregnancy.

o Each contraction last 20-30 seconds about 15-20 minutes apart.

o Some women have “false labor” called Braxton hicks contractions.

o Each contraction is recurring and may become stronger.

o Prior to the first stage of parturition, there can be a “blood show”, caused by a mucous plug from the cervical canal.

o The plug prevents bacteria and sperm from entering the uterus during pregnancy.

· Stage 1

o The amniotic fluid is released which is often called “breaking water”

o The cervix dilates.

· Stage 2

o The child is born.

o Sometimes an episiotomy is preformed which is a cut around the vagina to deliver the baby. The incisions are later sewn together.

· Stage 3

o The afterbirth or placenta is expelled.

o About 15 minutes after delivery the contractions shrink the uterus and removal of the placenta.

Process of Birth

5. Development After Birth

· Development after birth consists of infancy, childhood, adolescence, and adulthood.

· Aging encompasses progressive changes from about age 20 on that contribute to an increased risk of infirmity, disease, and death.

· Hypotheses of Aging

o Aging may have a genetic basis.

o Aging may be due to changes that affect the whole body.

o Aging may be due to extrinsic factors (diet and exercise).

· Effect of Age of Body Systems

o Deterioration of organ systems can possibly be prevented or reduced in part of utilizing good health habits.

o Skin becomes thinner and less elastic. The number of elastic fiber decreases and the collagen fiber go through cross-linking.

o Less adipose tissue in the subcutaneous layer, therefore, older people will feel cold.

o Cardiovascular disorder is the leading cause of death. The heart shrinks because of a reduction in cardiac muscle cell size.

· The best way to stay healthy through aging is by healthy eating habits.

6. Picture References

http://www.chariho.k12.ri.us/cms/library/images/reproduction/fertilization1.jpg

http://faculty.southwest.tn.edu/rburkett/human_1.jpg

http://universe-review.ca/I10-13-layers.jpg

http://img.tfd.com/dorland/thumbs/circulation_fetal.jpg

http://images.main.uab.edu/healthsys/ei_0401.gif

This Unit..

2008-04-14T20:18:00.001-07:00

REGARDING YOUR OWN PERFORMANCE

1. What were the three aspects of the assignments I've submitted that I am most proud of?
Both of my Compendium Review and my lab on leeches. I learned a lot about leeches and experiments they are put through. I worked hard on my compendium reviews and I know it shows that understand the chapters.

2. What two aspects of my submitted assignments do I believe could have used some improvement?
I would say my quizzes. I felt rushed or I rushed myself. I need to have a good pace at it and not rush myself. I know I could have put more work in my “build a limb” project but I still think I did a good job on it.

3. What do I believe my overall grade should be for this unit?
I did do all the work and I think I covered everything that should be covered so I think I deserve a A.

4. How could I perform better in the next unit?
Getting most of the work done early and do better on my quizzes. The next unit is our last unit so I will word harder on my labs!!!

REGARDING THE UNIT
1. At what moment during this unit did you feel most engaged with the course?
I got into the skeletal system chapter. I enjoyed reading about how the bone repair itself because my mom recently injured her ankle.

2. At what moment unit did you feel most distanced from the course?
I got lost in the nervous system but after doing the “build a limb” lab I now understand how it all connects to the muscle and skeletal systems.

3. What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
I noticed I got more emails from the instructor about deadlines.

4. What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
The “build a limb” was confusing at first but after I figured out what I wanted to use it wasn’t so confusing anymore.

5. What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.)

That I build a LIMB “arm”!! I wasn’t too sure if I would get into the chapters but I did. The muscle system was interesting to read because I made exercise a daily routine, well not daily but weekly.

Excerise!!!!

2008-04-14T19:48:00.000-07:00

Always on the go is my daily routine. I get up at 4:30 am every morning and I’m at work at 5:30 am till 2pm. After that I have a lunch with my son, get time to relax, get dinner going then end my day with doing homework. So can I get exercise to fit in my daily life? YES! I can, anyone can if they truly wanted it. I recently started to exercise and found that it helps me stay energized all day long till I go to bed at night. The beginning is always the hardest and I think that is why many quit. Many start exercise for the first week and quit. Maybe they started out too much and felt exhausted after and felt sore the next day. Who wants to deal with that all day? So I think that is one main reason why many quit. So if exercise is not for them they cut back on what they are eating. Some cut back too much and that it catches up to them and then they pig out! Exercise is for everyone and if they want to avoid health risk they should exercise.

Today there are many gyms in cities, YMCA in small communities so why isn’t exercise working? Why is there so many obese? Today we have many technology like video games, television, cell phones and Internet which all don’t include any active activity. We live in a society of fast food and on the go. Being on the go and using one of today’s technologies making society lazier than ever. No body wants to exercise. Yes we all want to be healthy and fit but we want it now not something we have to work for.

As a society we all need to take a good look at ourselves and ask if we really want to be in an obesity world. Many will say no and we should do something about it. Maybe make a gym with cheaper membership prices and more town activities for the whole family.

When I walk around the grocery store I notice that it’s cheaper to eat fatty food than healthy food. I wish healthy food didn’t cost so much, that having a membership at local gym didn’t cost 50 dollars. So I decided I can GROW my own healthy food and make my own gym at home.

Children are so inactive that we need to focus on them. They are our future. We need to stop sitting our children in front of the TV, playing video games and go play outside with them. If they learn active activity at an early age it can save them from many health complications.

Build a Limb

2008-04-14T18:01:00.000-07:00

In this lab I created a moving limb with neuron triggering muscle to pull on the bone to make the joints move. It will show the major parts to make the limb move. My objective is to present each steps it takes to move a muscle/arm.

Items used:

Two brown bags-the arm
Clothing pin-joint
Silver tape- showing where the muscles are located
Pink highlighter-muscles
Black marker-ligaments
Crayons-Thick Filament
Q-tips- Thin Filament
Fabric Softener-Sarcolemma
Straws-Myofibril
Penny-nucleus
Hair Tie-T Tubule
Chocolate-Troponin
Straw-Actin Filament
Wraps-Tropomyosin
Cheerio- Calcium
Black marks- Myosin Binding Sites
Chocolate- Sensory Receptor
Beans-Cell body
Cookies-Myelin Sheath
Rope- axon
End of the robe- axon terminal

The image is of a skeletal muscle in the arm. It contains the bones that are in the arm the ulna, radius and the humerus. Also it shows where the muscles are located. When moving the clothing pin around it shows that the arm is moveable.

This image shows what sarcomere looks like when it is relaxed. Sarcomeres are one of many units, arranged linearly within a myofibril, whose contraction produces muscle contraction. It contains two type of protein called myosin, and actin. The Thick filaments contain myosin. The Thin filaments contain actin.

This image shows what happens what the sarcomere are contracted. This is what happens when you tighten your muscles in your arm. Also this is called a sliding filament model, its the movement of actin filament in relation to myosin filament. the ATP supplies the energy for the muscle contractions.

Muscle Fiber

A muscle fiber is a cell containing the usual cellular components. The plasma membrane is called the sarcolemma, the sarcolemma forms T tubules that penetrate into the cells that they come into contract. The sarcoplasmic reticulum encases hundreds and some times even thousands of myofibrils. the sarcoplasm contain glycogen which is energy for the muscle contraction.

Calcium Binds to Troponin

Exposing myosin binding sites

Calcium binds to troponin, exposing myosin-binding sites. When calcium ions are released from the sarcoplasmic reticulum they combine with troponin and this causes the tyopomyosin threads to shift their position, exposing myosin-binding sites. The second image is when the muscles are contracted meaning the muscle has been pulled. Calcium ions are essential for muscle contraction.

This image is showing the neuron structure. The Myelin sheath contains Schwann cells. This image works with the CNS (central nervous system), which sends signals to the sensory fiber to move the muscle. There is three steps the nervous system does to function, which is to: sensory neurons, interneuron and motor neurons. The sensory neurons take nerve impulses from sensory receptors to the CNS. Interneuron occurs within the CNS. Then the motor neurons take nerve impulses from the CNS to the muscles.

Conclusion:
Each picture represents a function in the body to move the muscle. Each explains what function does to make the movement and what is involved with muscle contractions.
I thought this lab was more difficult than the other units because it was actually making an arm and making it move!! I did not have any way of showing a video of the arm moving but if you look closely to the picture it can move. Overall this was a good way of understand the muscle and it’s movements.

How the muscle works

2008-04-13T16:48:00.000-07:00

How Does The Muscle Work?
This lab is about the muscle contraction and how the body reacts to different experiences. With each experiment it will demonstrate what will happen when the body reacts to temperature and fatigue and show the effects to the muscle.
I hypothesis that temperature will slow my body down in forming a fist the first few seconds then will return to normal. After a few reps of squeezing a ball in my hand that it will slow down my reps also. I will attempt to prove that the temperature and fatigue will slow down the muscles contractions.

First experiment: the effect of temperature
I will form a fist for 20 seconds. After I record how many I did I will put my whole hand in an ice bowl for a minute then try again forming a fist for 20 seconds.
Temp----------number of fist
Normal--------44
Ice water------36

My hand in bowl of ice!

Second experiment: the effect of fatigue
I will count how many times I can squeeze a ball for 20 seconds and do it at least 10 times without stopping.
Reps number of times
One---------------45
Two--------------45
Three-------------45
Four--------------44
Five--------------43
Six----------------40
Seven-------------40
Eight -------------35
Nine---------------30
Ten----------------27

Squeezing a ball

ANALYSIS OF DATA:

1. What are the three changes you observed in a muscle while it is working (contracted)?
I was moving my flexor carpi and some of the extensor carpi muscle in both exercise. The flexor carpi muscle is in my wrist and hand that I was using to form a fist. With each fist I made I was also using some of my extensor carpi muscle, which is to straighten my wrist and hand. Each time I made a fist I was tightening my muscle.
2. What effect did the cold temperature have on the action of your hand muscles? Explain.

When I first put my whole hand in a bowl of ice water I knew it was going to be tuff because my hand was so cold in the first 15 seconds!! After my minute was up forming a fist was slow because my hand and fingers felt tight, then my hand started to get warm then it was back to normal in my last 5 seconds.

1. What are the three changes you observed in a muscle while it is working (contracted)?
Just like my first experiment I was using my flexor carpi and extensor carpi muscle. I noticed without stopping after my first 5 reps of squeezing a ball my wrist was getting tight and it was making it harder for my fingers to keep squeezing the ball.

2. What effect did fatigue have on the action of your hand muscles? Explain.
Without stopping after each reps my hand especially my wrist was getting tired and tight. The first few 20 seconds were okay but after 5 tries my wrist was getting tired and it was making it harder to keep squeezing the ball. My squeezes weren’t so tight because my fingers were getting tired.

Conclusion:
The brain sends signal to the nerve cells telling the muscle to contract. A muscle is a bundle of many cells called fibers. A muscle fiber contains many myofibrils, which are full of muscle proteins. Protein allows the muscle cell to move. The thick and thin filaments do the actual work of muscle movement.
After doing both experiments my body did have a reaction to temperature and fatigue. My hypothesis did come out correct. I knew that after my hand would warm up it would come back to normal and that after a few reps that my wrist would get tired.

http://nobelprize.org/nobel_prizes/medicine/laureates/1992/illpres/muscle-7.gif

This Image shows the steps on how the muscle contracts and is need to make it all work.

This image shows how the muscle works. The top image shows how the muscle is relax then what happens what its contract, if you notice the second image, it shows that the muscle gets tight when its contacted.

Chapter 11 & 12

2008-04-12T15:15:00.001-07:00

Chapter 11

Skeletal System

Overview of skeletal system
Bone growth, remodeling, and repair

3. Bones of the axial skeleton

4. Bones of the Appendicular Skeleton

Articulations
Picture References

Overview of skeletal system

The human body has 206 bones
The skeletal system consists of the bones along with the cartilage and fibrous connective tissue, which occurs in the ligament at the joints.
Function of the Skeleton
The skeleton supports the body
Protects soft body parts
Produces blood cells
Stores mineral and fat
Along with the muscles, permits flexible body movement
Anatomy of a Long Bone

Picture of A Long Bone Picture of the compact bone and Spongy

The main portion of the bone is called the diaphysis.
Compact bone is highly organized and composed of tubular units called osteons.
Spongy bone has an unorganized appearance. It contains numerous thin plates separated by unequal spaces.
Cartilage is not as strong as bone, but it is more flexible because the matrix gel-like and contains many collagenous and elastic fibers.

o Cartilage has no nerves and no blood vessels, making it harder to heal.

o Three types of cartilage:

1. Hyaline cartilage covers the end of the long bone. Is firm and somewhat flexible.

2. Fibro cartilage is stronger than hyaline cartilage because the matrix contains wide rows of thick, collagen fibers.

3. Elastic cartilage is more flexible than hyaline cartilage because the matrix contains mostly elastin fibers.

Fibrous connective tissue contains rows of cells called fibroblast separated by bundle of collagenous fibers. This tissue makes up ligaments that connect bone to bone and tendons that connect muscles to a bone at joints.

Bone growth, remodeling, and repair

Bones can grow throughout a lifetime because they are able to respond to stress by changing size, shape, and strength.
Bones are composed of living tissues
Cells involved in growth, remodeling, and repair of the bone are:

o Osteblasts-are bone-forming cells. They secrete the organic matrix of bone and promote the deposition of calcium salts into the matrix.

o Osteocytes-are mature bone cells derived from osteoblasts. They maintain structure of bone.

o Osteoclasts-are bone-absorbing cells. They break down bone and assist in depositing calcium and phosphate in the blood.

Bone Development and Growth
Ossification refers to the formation of bone.
Intramembranous ossification: bones develop between sheets of fibrous connective tissue.
Endochondral ossification: cartilaginous models of the bones are replaced by calcified bone matrix.
Bone growth is affected by vitamin D, growth hormone, and sex hormones.
Bone Remodeling and Its Role in Homeostasis
Bone remodeling is the renewal of bone. Osteoclasts break down bone and osteoblasts re-form bone. Some bone is recycled each year.
Bone recycling allows the body to regulate blood calcium.
Bone remodeling also accounts for why bones can respond to stress.
Bone Repair
Repair of a fracture required four steps:

o Hematoma formation

o Fibrocartilginous callus

o Bony callus

o Remodeling

The Human Skeleton

Bones of the axial skeleton

The axial skeleton consists of:

o The skull

o The hyoid bone

o The vertebral column,

o And the rib cage.

The Human Skull Bones of the Face

The Vertebral Column The Rib Cage

The skull is formed by the cranium, which protects the brain and the facial bones.
The hyoid bone anchors the tongue and is the site of attachment of muscles involved with swallowing.
The vertebral column is composed of vertebrae separated by shock-absorbing disks, which make the column flexible. It supports the head and truck, protects the spinal cord, and is a site for muscle attachment.
The vertebral column consists of 33 vertebrae.
Rib Cage
The rib cage is composed of the thoracic vertebrae, ribs, costal cartilages, and sternum. It protects the heart and lungs.
The rib cage is part of the axial skeleton.
Protects the heart and lungs

Bones of the Appendicular Skeleton

The appendicular skeleton consists of the bones within the pectoral and pelvis girdles and their attached limbs.
The bodies have left and right pectoral girdles; each consists of a scapula and clavicle.
The pectoral girdles and upper limbs are adapted for flexibility.
The bones in the pectoral girdle are:

o Scapula, clavicle

o The upper limb: humerus, radius, ulna, carpals, metacarpals, phalanges

The pelvic girdle and the lower limbs are adapted for supporting weight; the femur is the longest and strongest bone in the body.
The bones in the pelvis girdle are:

o Two coxal bones

o The lower limb: Femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges.

Articulations

Bones are joined at joints, of which are thee types:

o Fibrous joints-are immovable

o Cartilaginous joints- is slightly movable.

o Synovial joints – are freely movable.

Movements Permitted by Synovial Joints
Intact skeletal muscles are attached to bones by tendons that span joints. When a muscle contracts, one bone moves in relation to another bone.

http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f6-4c_gross_anatomy_of__c.jpg

http://www.fluoridealert.org/pesticides/compact.spongy.bone.jpg?4abcc000

http://classes.midlandstech.com/bio112/figure7.5endochondral%20ossification.jpg

http://library.thinkquest.org/J0111100/graphics/skull1.JPG

http://biology.clc.uc.edu/graphics/bio105/skeleton.jpg

http://services.epnet.com/GetImage.aspx/getImage.aspx?ImageIID=4826

http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f7-28_vertebral_column_c.jpg

http://www.medicalook.com/systems_images/Rib_cage.jpg

Chapter 12

Muscular System

Overview of Muscular System
Skeletal Muscle Fiber Contraction
Whole Muscle Contraction
Muscular Disorders
Homeostasis
Picture References

Overview of Muscular System

Type Of Muscles

Humans have three type of Muscles tissues:

o Smooth Muscle- is involuntary, fibers are spindle-shaped cells, each with a single nucleus. Occurs in walls of internal organs.

o Cardiac Muscle- is involuntary, forms the heart wall.

o Skeletal Muscle- is voluntary; fibers are tubular, multinucleated, and striated. Is usually attached by tendons to the skeleton.

Functions of Skeletal Muscles

o Skeletal muscles support the body.

o Skeletal muscles make bones move.

§ Rigor mortis is the contraction of muscles at death due to ATP.

o Skeletal muscles help maintain a constant body temperature.

o Skeletal muscle contraction assists movement in cardiovascular and lymphatic vessels.

o Skeletal muscles help protect internal organs and stabilize joints.

Skeletal Muscles of the Body
Skeletal muscles are well organized.
Muscles are covered with fascia, a type of connective tissue that extends beyond the muscle and becomes its tendon.
Tendons quite often extend past a joint before anchoring a muscle to a bone.
When achieving movement, some muscles are prime movers, some are synergists, and other are antagonists.
Muscles are named for their size, shape, location, direction of fibers, number of attachments, and action.

The Muscle in the Human Body

Skeletal Muscle Fiber Contraction

Muscle Fibers and How They Slide
Muscle fibers contain myofibrils, and myofibrils contain actin and myosin filaments. Muscle contraction occurs when sarcomeres shorten and actin filaments slide past myosin filaments.
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular junctions.
Thick filaments- is composed of several hundred molecules of the protein myosin.
Thin filaments- primarily, a thin filament consists of two intertwining strands of the protein actin.
Sliding filaments- an explanation for muscle contraction based on the movement of actin filaments in relation to myosin filaments.
Control of Muscle Fiber Contraction
Muscle fibers are stimulated to contract by motor neurons whose axons are in nerves.
The role of ATP in muscle contraction is to supplies the energy for muscles contraction.

Skeletal muscle fiber and struture

Neuromuscular Juntion

Whole Muscle Contraction

Whole muscle contraction is dependent on muscle fiber contraction.
Muscles Have Motor Units
A muscle contains motor units: several fibers under the control of a single motor axon.
Motor unit contraction is described in terms of a muscle twitch, summation, and tetanus.
The strength of muscle contraction varies according to recruitment of motor units.
Summation is increased muscle contraction until maximal sustained contraction is called tetanus.
A whole muscle typically contains many motor units. As the intensity of nervous stimulation increases, more and more motor units in a muscle are activated. It is known as recruitment.
“Muscle tone” one desirable effect of exercise. The muscle is firm and solid.
Energy for Muscle Contraction
Muscles can use various fuel sources for energy and they have various ways of producing ATP during muscle contraction.
A muscle fiber has three ways to acquire ATP for muscle contraction

o Creatine phosphate transfers a phosphate to ADP and ATP results.

o Fermentation also produces ATP quickly. Fermentation is associated with an oxygen dept because oxygen is needed to metabolize the lactate that accumulates.

o Cellular respiration provides most of the muscle’s ATP but takes longer because much of the glucose and oxygen must be transported in blood to mitochondria. Occurs during exercise.

Fast twitch fibers are usually anaerobic and seem to be designed for strength because their motor units contain many fibers.

o Helpful in sport activities like, weight lifting, sprinting or golf clubbing.

o Is anaerobic

o Has explosive power

o Fatigues easily

Slow twitch fibers have a steadier tug and have more endurance despite more units with smaller number of fibers.

o Helpful with running distances, biking and jogging.

o Is aerobic

o Has steady power

o Has endurance

Delayed Onset Muscle Soreness

o Appears 24-48 hours after vigorous exercise.

o Many be due to tissue injury that takes several days to heal.

o To prevent “DOMS” try warming up before working out and cooling down completely.

o Avoid making sudden MAJOR changes in a exercise routine.

Muscular Disorders

Common Muscular Conditions

o Spasms- are sudden and involuntary muscular contractions most often accompanied by pain.

o Convulsion- multiple spasms of skeletal muscles are seizure.

o Cramps- are strong, painful spasms, especially of the leg and foot, usually due to vigorous activity.

o Facial tics- periodic eye blinking, head turning, or grimacing, are spasms that can be controlled voluntarily, by only with great effort.

o Strains- is caused by stretching or tearing of a muscle

o Sprain- is a twisting of a joint leading to swelling and injury, not only of muscle but also of ligaments.

Muscular diseases

o Myalgia- refers to achy muscles. Caused by overusing or overstretching of a muscle or group of muscles.

o Fibromyalgia- is a chronic condition whose symptoms include achy pain, tenderness, and stiffness of muscles.

o Other diseases are:

§ Muscular dystrophy

§ Myasthenia gravis

§ Amyotrophic lateral sclerosis (ALS)

Muscle disorder location in the body

Homeostasis

Body Systems Produce Movement
Movement is essential to maintaining homeostasis.
The skeletal muscular systems work together to enable body movement.
The muscles and bones produce movement and protect body parts.
The bones produce red blood cells and are involved in the regulation of blood calcium levels.
The muscles produce the heat that gives us a constant body temperature.

http://medicalimages.allrefer.com/large/tissue-types.jpg

http://www.drstandley.com/images/muscular.bmp

http://www.octc.kctcs.edu/gcaplan/anat/images/Image286.gif

http://www.lib.mcg.edu/edu/eshuphysio/program/section2/2ch1/2ch1img/neuromus.jpg

http://www.healiohealth.com/Library/Images/Muscle-Disorders.jpg

LEECH NEUROPHYSIOLOGY LAB

2008-04-10T16:57:00.000-07:00

LEECH NEUROPHYSIOLOGY LAB

· What is the electrode measuring?

Electrodes are what you use to record the activity of the neurons. The generic term "electrode" is defined as a conductor that is used to establish electrical contact with a nonmetallic substance. With the use of florescent dye the neurons can be seen using a dissection microscope.

· Why use leeches in neurophysiology experiments?

Leeches have been useful in many experiments in the function of the nervous system. Leeches have a simple nervous system so it’s easier to understand. Many first discoveries were found in leeches. Leeches has 21 segmental ganglia, each containing 175 pairs of neurons. The reasonably small number and the large size of the neurons have made leeches favorite subjects of neurobiologists.

· What is the difference between a sensory and a motor neuron?

Sensory neurons take nerve impulses or messages from a sensory receptor to the CNS. The Motor neuron takes nerve impulse away from the CNS to effectors. The difference between both is that they both take nerve impulses to different locations. The sensory sends messages to the CNS and motor neuron takes it away from the CNS.

· Do you think a leech experiences pain? What is pain?

Leeches have a nervous system so I would believe that they feel some sort of pain during experiences. During this experience, the leech was dipped in 20% ethanol solution. It can be use for smaller creature as an anesthesia like a leech that breathes through their skin. Pain is an unlikable sensation. When there is harm done to our bodies to any creature’s bodies it can cause a discomfort or agony.

· What were the two most interesting things about doing this lab?

To dissects a leech online. After doing this experiment I never knew anything about leeches and how useful they have been in discovering many functions with the nervous system. To learn more about neurons and how it looked after I put the florescent dye in and then the light and how each neuron look different from one another. The pictures of the neurons were specific because I felt like I was really doing the experiment even if it was on a computer.

· Anything you found confusing or didn't like about the lab?

It took me awhile to figure out how to actually get a neuron at first but other than that it was a great lab!

an Image of the leech with the oscillope trace.

Cell Types that are inside a Leech's Nervous System

A screen shot of a R Cell that was found in the leech's nervous system.