Compendium Review Unit 4- Human Populations: Reproduction and Ecology- Topic 2- Human Landscapes
Chapter 22- Human Evolution
22.1- Origin of Life
22.2- Biological Evolution
22.3- Classification of Humans
22.4- Evolution of Hominids
22.5- Evolution of Humans
22.1- Origin of Life
A chemical evolution produced the first cells. The sun and the planets were formed probably over a 10 billion year period. 4.6 billion years ago the solar system was in place. The Earth’s atmosphere was very hot at first and the water was existing only as a gas which formed thick, dense clouds. But once the Earth cooled down the water vapor condensed to liquid water and rain began to fall. So much rain fell that the oceans were formed. There were a lot if sources for energy then such as volcanoes, meteorites and lightning. The RNA- first hypothesis consists of only the macromolecule RNA was needed to progress toward formation of the first cells. RNA can be a substrate and an enzyme during RNA processing. Because DNA is a double helix and is more stable it rather than RNA became permanent genetic material. Cells have lipid-protein membranes. Protocell’s carry on metabolism but not reproduce. A heterotroph is an organism that takes in preformed food.
22.2- Biological Evolution
The process of which a species changes through time is known as biological evolution. 2 important aspects of this are descent from a common ancestor and adaptation to the environment. If adapted it is able to survive and reproduce in the environment. Fossils are the actual remains of species that lived 10,000 years ago and more. These are traces that any past life existed, such as trails, footprints, burrows and preserved droppings. Weathering and erosion of rocks produces an accumulation of particles that vary in size and nature are call sediment. Sedimentation has been going on since the Earth was formed. This can take place on land or in bodies of water. For fossils to be dated sediment becomes a layer in a sequence of layers. The older layer is above and younger than the one directly below. The fossil record, history of life recorded by fossils, is evidence that evolution has occurred. The first signs of life in this record are unicellular prokaryotes, then unicellular eukaryotes and then multicellular eukaryotes. Fossils that have characteristics of 2 different groups are transitional fossils. Whales had terrestrial ancestors. The earliest mammals were shrew size creatures in fossil beds about 200 million years old.
The study of the distribution of plants and animals in different places around the world is known as biogeography. Homologous structures are structures that are anatomically similar because they are inherited from a common ancestor. Now structures that are not constructed similarly and do not have a common ancestry, but do serve the same function are known as analogous structures. Vestigial structures inherit their anatomy from their ancestors, they are anatomical features that are fully developed in one group but reduced in other similar groups. Biochemical evidence shows that all living organisms use the same biochemical molecules. They use the same DNA and 20 amino acids in their proteins. Humans share a lot of genes with simpler organisms. A small protein in the electron transport chain that plays an important role is known as cytochrome c, this shows that humans differ from monkeys by 2 amino acids. Charles Darwin believed in natural selection, that is species become adapted to their environment. There are three elements for the natural selection process, variation- physical variation can be passed on, individuals vary in physical characteristics, competition for limited resources- numbers in generation stay about the same due to food competition and resources, adaptation- the environment selects for better adapted traits.
22.3- Classification of Humans
The binomial name of an organism is what gives its genus and species. Those in the same domain have only general characteristics in common, while those in the same genus have specific characteristics in common. Major decisions regarding history of life come down to DNA/rRNA/protein sequencing table. Mitochondrial DNA helps decide timing of recent evolutionary events because it changes frequently. Primates are adapted to living in trees. They have mobile limbs, grasping hands, large complex brains, binocular vision, flattened face, and reduced reproductive rates. 2 suborders make up the order of Primates, lemurs, tarsiers and lorises make up the prosimians and monkeys, apes and humans make up anthropoids. The hands and feet of primates have 5 digits each and the opposable thumb helps for grasping and a powerful grip.
22.4- Evolution of Hominids
Evolutionary trees are working hypothesis of past history for characteristics of a group organisms in which biologists have studied. The belief that humans evolved from apes is one that Darwin believes and is a misconception. Humans and apes are believed to have a common ape like ancestor. For 7 million years humans and apes have been separately evolving from a common ancestor. Hominids refer to our branch of the evolutionary tree. If a fossil is in the hominid line of descent that means it is closer to us than to the African apes. If 2 lines of descent called a lineage diverge from a common ancestor then the genes and proteins of the 2 lineages are nearly identical. The protein changes and RNA changes are because with each lineage genetic changes accumulate. Some features of hominids are walking on two feet, shape of face and brain size. The human jaw is shorter than an apes jaw. A brain of a chimpanzee is 400 cm3 in size while a human brain is that of 1,300 cm3. Fossils from when apes and human lineages split have been found. The oldest fossil is from 7 MYA called Sahelanthropus tchadensis. It was found in central Africa. It was a skull. The orrorin tugenensis is from 6 MYA and also found in Africa.
22.5- Evolution of Humans
Fossils are assigned to the genus Homo if the brain size is 600 cm3 or greater, if the jaw and teeth resemble those of humans and if tool use is evident. Homo habilis may be ancestors to modern humans dated between 2.0 and 1.9 MYA. Culture depends on capacity to speak and transmit knowledge. Homo erectus was the first hominid to use fire and fashioned more advanced tools. Scientists accept that homo sapiens evolved from H. erectus. The out-of-Africa hypothesis proposes H. sapiens evolved from H. erectus but only in Africa and then they migrated to Europe and Asia. Many scientists support this hypothesis. There is a Neandertal skeleton from 200,000 years before present, they get their name from Neander Valley, Germany. The out-of-Africa hypothesis says they were supplanted by modern humans. They were culturally advanced, they lived in caves. The oldest fossils to be designated as homo sapiens are known as cro-magnons. These might have been the first to have a language. They painted drawings of animals on the cave walls in Spain and France.
Chapter 23- Global Ecology and Human Interferences
23.1- The Nature of Ecosystems
23.2- Energy Flow
23.3- Global Biogeochemical Cycles
23.1- The Nature of Ecosystems
Organisms found on Earth are in the biosphere, this is one giant ecosystem. An ecosystem is a place where organisms interact with themselves and with the physical and chemical environment. Biomes are distinctive terrestrial ecosystems, such as temperature and rainfall define the biomes containing communities of organisms adapted to regional climate. Aquatic ecosystems are divided into those composed of freshwater and those composed of salt water. The ocean being a marine ecosystem covers 70% of the Earth’s surface. Standing water and fresh water make up 2 freshwater ecosystems. Abiotic components of an ecosystem are the nonliving components. Biotic are living things that can be categorized according to the food source. These are autotrophs, and some heterotrophs. Autotrophs require inorganic nutrients and outside energy sources for production of organic nutrients for own use and others of the community. These are producers because they produce food. Heterotrophs need a source of organic nutrients. These are consumers because they consume food. Herbivores eat plants and algae. Carnivores eat other animals. Omnivores eat both. Detritus feeders eat decomposing particles of organic matter. Niche is the role of an organism in an ecosystem. Energy flow and chemical cycling characterizes every ecosystem.
23.2- Energy Flow
Shortness of food chains can be attributed to loss of energy between trophic levels. An ecological pyramid shows the flow of energy with large losses between successive trophic levels. Biomass is the number of organisms multiplied by the weight of organic matter within one organism, pyramids of this eliminate size as a factor.
23.3- Global Biogeochemical Cycles
Organisms require a variety of organic and/or inorganic nutrients. Biogeochemical cycles are pathways that chemicals circulate through involving living and nonliving components. The water cycle shows transfer rate of water between components of an ecosystem. Evaporation is the sun rays causing freshwater to evaporate from seawater, leaving salts behind. The vaporized water rises, condenses and then falls as precipitation. Also evaporates from plants and land. Because of gravity freshwater eventually returns to the see. If water doesn’t run off it can sink or percolate into the ground saturating the earth. Top saturation zone is called the water table. Aquifers are rock layers that contain water, releasing it to wells or springs. Interference from humans includes withdrawing water from aquifers, clearing vegetation from land and natural processes which purify water. Groundwater mining refer to withdrawals from aquifers exceeding the possibility of recharge.
The carbon cycle consists of carbon dioxide in the atmosphere, where the exchange pool is. Terrestrial and aquatic ecosystems exchange carbon dioxide with the atmosphere. Respiration and combustion add carbon dioxide to the atmosphere. It is recycled to plants. Greenhouse gases allow solar radiation to pass through but hinder the escape of heat back into space. The rise in the Earth’s temperature referred to as global warming is because of the greenhouse effect. If the temperature continues to rise more water will evaporate, making more clouds which could increase this more. Coastal areas could disappear as water continues to rise.
78% of atmosphere is nitrogen gas, plants cannot make use of this. Production of nitrates during the nitrogen cycle is called nitrification. This can occur by Nitrogen gas turns into nitrate in the atmosphere when cosmic radiation provides the high energy needed. Denitrification is the process which nitrate converts back to nitrogen gas. Human activities alter transfer rates in this cycle by producing fertilizers. When fertilizers run off into lakes and rivers the algae overgrows. Acid deposition is when nitrogen oxides and sulfur dioxide enter the atmosphere from fuel of burning fossils.
The phosphorus cycle has three components known as reservoir, exchange pool and biotic community. Bacteria converts nitrogen gas to ammonium. Cultural eutrophication is the overenrichment of waterways which the runoff of fertilizer can cause. Biological magnification is the process of substances becoming more concentrated in organisms in higher trophic levels. Many species are almost to the point of extinction because of humans polluting the seas and exploiting their resources.
Friday, December 12, 2008
Thursday, December 11, 2008
Self Unit Evaluation
REGARDING MY OWN PERFORMANCE
1. What were the three aspects of the assignments I've submitted that I am most proud of?
I am proud of all three of my labs, the 2 online labs and the major lab project.
2. What two aspects of my submitted assignments do I believe could have used some improvement?
I could have done so much better on my ethical issues essay and my second compendium review, I was preparing finals for my other class and got behind so I had to give a little on these. My mistake I know! I wanted to do the extra credit as well, but again I had to work on other finals.
3. What do I believe my overall grade should be for this unit?
My overall grade should be a high B I think, for most of my work I was pretty thorough I believe.
4. How could I perform better in the next unit?
Well, there what be a next unit, which is good and bad! :) I've enjoyed this class, but I'm looking forward the the few weeks of not worrying about school!!
REGARDING THE UNIT
1. At what moment during this unit did you feel most engaged with the course?
I was most engaged during the reproduction portion, my sister just found out she's pregnant so it was interesting reading about the different stages and whats going on with the baby.
2. At what moment unit did you feel most distanced from the course?
I was most distance from unit two, when reading and doing my compendium review, maybe it's the jitters of knowing that I'm almost done! :)
3. What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
Your (Mr. Frolich) ideas for the big lab project where helpful for me in getting started with mine. It got the ball rolling I should say!
4. What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
The ethical issue essay for some reason I couldn't get my brain wrapped around, I obviously could have put more thought and work into it as well. But this was the most confusing part for me this unit.
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.)
It was most surprising reading about all the things that babies develope in just the first few weeks. I couldn't believe how quickly the nervous system, heart, fingernails, eyes, nose and ears come. It is so facinating how a life is created!!!
1. What were the three aspects of the assignments I've submitted that I am most proud of?
I am proud of all three of my labs, the 2 online labs and the major lab project.
2. What two aspects of my submitted assignments do I believe could have used some improvement?
I could have done so much better on my ethical issues essay and my second compendium review, I was preparing finals for my other class and got behind so I had to give a little on these. My mistake I know! I wanted to do the extra credit as well, but again I had to work on other finals.
3. What do I believe my overall grade should be for this unit?
My overall grade should be a high B I think, for most of my work I was pretty thorough I believe.
4. How could I perform better in the next unit?
Well, there what be a next unit, which is good and bad! :) I've enjoyed this class, but I'm looking forward the the few weeks of not worrying about school!!
REGARDING THE UNIT
1. At what moment during this unit did you feel most engaged with the course?
I was most engaged during the reproduction portion, my sister just found out she's pregnant so it was interesting reading about the different stages and whats going on with the baby.
2. At what moment unit did you feel most distanced from the course?
I was most distance from unit two, when reading and doing my compendium review, maybe it's the jitters of knowing that I'm almost done! :)
3. What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
Your (Mr. Frolich) ideas for the big lab project where helpful for me in getting started with mine. It got the ball rolling I should say!
4. What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
The ethical issue essay for some reason I couldn't get my brain wrapped around, I obviously could have put more thought and work into it as well. But this was the most confusing part for me this unit.
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.)
It was most surprising reading about all the things that babies develope in just the first few weeks. I couldn't believe how quickly the nervous system, heart, fingernails, eyes, nose and ears come. It is so facinating how a life is created!!!
Unit 4- Ethical Issue Essay
Who Should Reproduce?
I believe that the U.S. should no be so worried about under-developed or third world countries reproducing when the "typical U.S. child consumes the same resources as 30 children in India and 300 children in Ethiopia." This is crazy! I agree that population growth can put a strain on resources, I mean then more people are using them up, and espescially for the U.S. if they are being used at that rate. If parents would get the conserving resources or use sparingly ideas into their kids heads then maybe it would help to consume less and preserve more. I'm sure more resources would be available if there was a decrease in population, however though deaths are occuring babies are also being born. It shouldn't have to come to the point where we have to dictate how many kids someone can have or who can have them, we should have the commonsense to know what is happening and what we can or can't do to help. I believe population growth should be worried about if we continue to use all the resources the way and at the rate that we do, before it's too late!
I believe that the U.S. should no be so worried about under-developed or third world countries reproducing when the "typical U.S. child consumes the same resources as 30 children in India and 300 children in Ethiopia." This is crazy! I agree that population growth can put a strain on resources, I mean then more people are using them up, and espescially for the U.S. if they are being used at that rate. If parents would get the conserving resources or use sparingly ideas into their kids heads then maybe it would help to consume less and preserve more. I'm sure more resources would be available if there was a decrease in population, however though deaths are occuring babies are also being born. It shouldn't have to come to the point where we have to dictate how many kids someone can have or who can have them, we should have the commonsense to know what is happening and what we can or can't do to help. I believe population growth should be worried about if we continue to use all the resources the way and at the rate that we do, before it's too late!
Wednesday, December 10, 2008
Unit 4- Online Lab- Topic 2- Human Landscapes
This lab is to help me see how demographics, or the characteristics and distribution of human populations affects resource consumption.
What was your high fertility rate country and what was its fertility rate?
My high fertility rate country was East Africa. The fertility rate was a little over double the World's coming in at 6.70 compared to the World at 3.20.
What was your low fertility rate country and what was its fertility rate?
My lower fertility rate country was the Bahamas. The fertility rate was a little lower, but not as low as others. The rate there was 2.20.
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?
This results because there are people have babies, putting those babies at the same age and it becomes a continued cycle of production rate, that seems to pick up speed along the way. :) I think the population growth may become more wide spread, but still be happening.
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.
This wasn't the case with my graph, but I think this leads to more middle-aged people because of higher infant deaths or younger generations moving around instead of populating that area maybe.
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.
Where more older people are I see a lot of medical offices for the sick and not as much cheer. For a more younger populated area I see not a lot of help from them and yet more resources to help them. I see more laughter and the busy life style.
What was your high fertility rate country and what was its fertility rate?
My high fertility rate country was East Africa. The fertility rate was a little over double the World's coming in at 6.70 compared to the World at 3.20.
What was your low fertility rate country and what was its fertility rate?
My lower fertility rate country was the Bahamas. The fertility rate was a little lower, but not as low as others. The rate there was 2.20.
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?
This results because there are people have babies, putting those babies at the same age and it becomes a continued cycle of production rate, that seems to pick up speed along the way. :) I think the population growth may become more wide spread, but still be happening.
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.
This wasn't the case with my graph, but I think this leads to more middle-aged people because of higher infant deaths or younger generations moving around instead of populating that area maybe.
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.
Where more older people are I see a lot of medical offices for the sick and not as much cheer. For a more younger populated area I see not a lot of help from them and yet more resources to help them. I see more laughter and the busy life style.
Unit 4- Online Lab- Topic 1- Reproduction
This lab shows what I believe are 10 significant events for fetal development..
The 1st event would have to be conception, since this is where it all begins...
Next the 3rd week is significant because the nervous system is being built and the beginning of the heart. These are two very important systems!!!
Then the 4th week, the heartbeat can be heard on an ultrasound, though I've never been pregnant I think this would be a moving experience. This is important because a good strong heartbeat can make you believe in a good healthy pregnancy and baby!
During the 5th week the eyes, ears and nose become noticeable and during the
6th week fingers and toes.. It's nice to see these parts show up and be accounted for!
The 3rd month is when you can learn the sex of your baby and when they get fingerprints. This is important to many women I know, since the nursery is waiting on it.
The 4th month the heartbeat can be heard with the stethoscope, no longer just the ultrasound picking up this sound. Again, more signs of a healthy baby.
The 5th month is when the mother can begin to feel her baby moving around.Though I've heard that babies can make kicks and jabs hurt, its special to feel that moving inside of you.
The 7th month the eyes are open, how special!
And the 9th month, time for delivery! A special baby is born!! This is a picture of my nephew!
The 1st event would have to be conception, since this is where it all begins...
Next the 3rd week is significant because the nervous system is being built and the beginning of the heart. These are two very important systems!!!
Then the 4th week, the heartbeat can be heard on an ultrasound, though I've never been pregnant I think this would be a moving experience. This is important because a good strong heartbeat can make you believe in a good healthy pregnancy and baby!
During the 5th week the eyes, ears and nose become noticeable and during the
6th week fingers and toes.. It's nice to see these parts show up and be accounted for!
The 3rd month is when you can learn the sex of your baby and when they get fingerprints. This is important to many women I know, since the nursery is waiting on it.
The 4th month the heartbeat can be heard with the stethoscope, no longer just the ultrasound picking up this sound. Again, more signs of a healthy baby.
The 5th month is when the mother can begin to feel her baby moving around.Though I've heard that babies can make kicks and jabs hurt, its special to feel that moving inside of you.
The 7th month the eyes are open, how special!
And the 9th month, time for delivery! A special baby is born!! This is a picture of my nephew!
Unit 4- Lab Project- List of Species
Yogurt- Lactobaccilus genus
This is my breakfast every morning. The relationship here is symbiotic, we eat this and it helps with our digestive tract but I can’t see the benefit for yogurt. I don’t believe that yogurt is domesticated
Goat- Capra Hircus
I had a pet goat when I was younger and now my grandparents have one. Goats are domesticated. The relationship is mutualistic, we keep them fed and they eat down all our weeds, this is a win-win situation
Peanuts- Arachis hypogea
Peanut butter is something I eat regularly. This is domesticated and the relationship here I would say is symbiotic. I enjoy peanuts, but I can’t see how they benefit from any of that.
Ecoli- Escherichia Coli
This is the bacteria that is found in the lower intestines of warm blooded animals, such as chickens. This is normal flora in the gut. The relationship between the animal and the flora is mutualistic because it helps with production of Vitamin K2, while the relationship in regards to humans is not good. This is a parasite, in which makes humans sick.
Tuna- Thunnus tonggol
The only kind of seafood I eat is tuna fish in the bumblebee can and fish sticks. The relationship here is mutualistic, they can live in our waters and we can eat them. I believe fish can be domesticated, but are not until we make them that way.
Spider Plant- Chlorophytum Comosum
The spider plant is domesticated. The relationship mutualistic I care for the plant keeping it well watered while it adds character to my entertainment center and puts off oxygen
Cat- Felis Catus
I have three cats myself, so I interact with them everyday! They are very much domesticated, and this relationship is mutualistic. I care for them giving them love and nourishment while they cuddle and keep it exciting around here
Bermuda Grass- Cynodondactylon
Bermuda grass is domesticated. This is a mutualistic relationship, it helps our homes to look pretty or allows a nice place to play and we take care of it maintaining its beauty.
Horse- Equus Saballus
I grew up around horses and I still see them at my sisters house every day or so. I believe horses are domesticated. The relationship here is mutualistic as well, we care for them and they can be loyal friends or used to ride around.
Chicken- Gallus Domesticus
I eat chicken and occasionally eggs. I see chickens as being domesticated. The relationship is mutualistic, we keep them safe from coyotes and foxes and in return we can eat their eggs or them.
Goldfish- Carassius Auratus
Goldfish are domesticated. This relationship is mutualistic, we benefit from having pretty fish to look at in a tank while they get to swim around and we keep them fed and their housing clean.
Pig- Sus Scrofa Domestica
I eat bacon, pork chops and chili out of pork. Pigs can be domesticated, I see this relationship as being mutualistic. We care for domesticated pigs and keep them fed, while in return we can butcher them for the meat.
Dog- Canis lupus familiaris
I believe dogs are domesticated. The relationship is mutualistic, we care for them and keep them fed while they are companions and protectors for us.
Willow tree- Salix
The willow tree is domesticated. The relationship is mutualistic, it provides shade and shelter to some while we care for and keep the tree trimmed.
Deer- Odocoileus Virginianus
Deer are not domesticated. I see this relationship as being mutualistic, they graze out in the wild and for sometime out of the year don’t have to be in fear, then when hunting season comes around they need to be in fear. But once we have hunted and killed them they are beneficial to us in return
Wheat- Triticum aestivum
I love spaghetti! So we eat this often in my house. Wheat is a big part of the pasta. I think wheat is domesticated. The relationship here I would say is also mutualistic, we tend to the wheat crops and in turn we get to eat it all up!
Cow- Bos Taurus
Cows are domesticated. The relationship is mutualistic. We give them fields to graze on and pastures to roam and if and when the time is right we can butcher them for meat. Also they can be rode and roped
Hawk- Order Falconiformes
I don’t believe that hawks are domesticated. We see then flying around. I see this relationship as mutualistic, we don’t hunt them and they keep our rodent population down and get road kill cleared up.
Carrot- Daucus Carota Sativus
I often eat carrots and ranch for a snack or on my salads. The relationship here is mutualistic, while we eat and enjoy carrots we also help them to grow and care for them as they are doing so. I believe carrots are domesticated.
Broccoli- Brassica oleracea italica
Broccoli is one of my favorite vegetables. I eat it whenever I can, I like it cooked or raw. Broccoli is domesticated. The relationship here is again mutualistic. We may get the upper hand at eating it but we also nourish it while its growing.
This is my breakfast every morning. The relationship here is symbiotic, we eat this and it helps with our digestive tract but I can’t see the benefit for yogurt. I don’t believe that yogurt is domesticated
Goat- Capra Hircus
I had a pet goat when I was younger and now my grandparents have one. Goats are domesticated. The relationship is mutualistic, we keep them fed and they eat down all our weeds, this is a win-win situation
Peanuts- Arachis hypogea
Peanut butter is something I eat regularly. This is domesticated and the relationship here I would say is symbiotic. I enjoy peanuts, but I can’t see how they benefit from any of that.
Ecoli- Escherichia Coli
This is the bacteria that is found in the lower intestines of warm blooded animals, such as chickens. This is normal flora in the gut. The relationship between the animal and the flora is mutualistic because it helps with production of Vitamin K2, while the relationship in regards to humans is not good. This is a parasite, in which makes humans sick.
Tuna- Thunnus tonggol
The only kind of seafood I eat is tuna fish in the bumblebee can and fish sticks. The relationship here is mutualistic, they can live in our waters and we can eat them. I believe fish can be domesticated, but are not until we make them that way.
Spider Plant- Chlorophytum Comosum
The spider plant is domesticated. The relationship mutualistic I care for the plant keeping it well watered while it adds character to my entertainment center and puts off oxygen
Cat- Felis Catus
I have three cats myself, so I interact with them everyday! They are very much domesticated, and this relationship is mutualistic. I care for them giving them love and nourishment while they cuddle and keep it exciting around here
Bermuda Grass- Cynodondactylon
Bermuda grass is domesticated. This is a mutualistic relationship, it helps our homes to look pretty or allows a nice place to play and we take care of it maintaining its beauty.
Horse- Equus Saballus
I grew up around horses and I still see them at my sisters house every day or so. I believe horses are domesticated. The relationship here is mutualistic as well, we care for them and they can be loyal friends or used to ride around.
Chicken- Gallus Domesticus
I eat chicken and occasionally eggs. I see chickens as being domesticated. The relationship is mutualistic, we keep them safe from coyotes and foxes and in return we can eat their eggs or them.
Goldfish- Carassius Auratus
Goldfish are domesticated. This relationship is mutualistic, we benefit from having pretty fish to look at in a tank while they get to swim around and we keep them fed and their housing clean.
Pig- Sus Scrofa Domestica
I eat bacon, pork chops and chili out of pork. Pigs can be domesticated, I see this relationship as being mutualistic. We care for domesticated pigs and keep them fed, while in return we can butcher them for the meat.
Dog- Canis lupus familiaris
I believe dogs are domesticated. The relationship is mutualistic, we care for them and keep them fed while they are companions and protectors for us.
Willow tree- Salix
The willow tree is domesticated. The relationship is mutualistic, it provides shade and shelter to some while we care for and keep the tree trimmed.
Deer- Odocoileus Virginianus
Deer are not domesticated. I see this relationship as being mutualistic, they graze out in the wild and for sometime out of the year don’t have to be in fear, then when hunting season comes around they need to be in fear. But once we have hunted and killed them they are beneficial to us in return
Wheat- Triticum aestivum
I love spaghetti! So we eat this often in my house. Wheat is a big part of the pasta. I think wheat is domesticated. The relationship here I would say is also mutualistic, we tend to the wheat crops and in turn we get to eat it all up!
Cow- Bos Taurus
Cows are domesticated. The relationship is mutualistic. We give them fields to graze on and pastures to roam and if and when the time is right we can butcher them for meat. Also they can be rode and roped
Hawk- Order Falconiformes
I don’t believe that hawks are domesticated. We see then flying around. I see this relationship as mutualistic, we don’t hunt them and they keep our rodent population down and get road kill cleared up.
Carrot- Daucus Carota Sativus
I often eat carrots and ranch for a snack or on my salads. The relationship here is mutualistic, while we eat and enjoy carrots we also help them to grow and care for them as they are doing so. I believe carrots are domesticated.
Broccoli- Brassica oleracea italica
Broccoli is one of my favorite vegetables. I eat it whenever I can, I like it cooked or raw. Broccoli is domesticated. The relationship here is again mutualistic. We may get the upper hand at eating it but we also nourish it while its growing.
Sunday, December 7, 2008
Compendium Review Unit 4/ Topic 1
Compendium Review Unit 4-Human Populations-Reproduction &Ecology—Topic 1-Reproduction
Chapter 16- Reproductive System
16.1- Human Life Cycle
16.2- Male Reproductive System
16.3- Female Reproductive System
16.4- Female Hormone Levels
16.5- Control of Reproduction
16.6- Sexually Transmitted Diseases
16.1- Human Life Cycle
The reproductive system for males and females are very different. Puberty is known as a sequence of events that take place for females around the age of 11 and 13 and for males 14 and 16; this is when they become sexually competent young adults. The reproductive system is fully functioning, (ability to produce children) when puberty in complete. In the reproductive system males produce sperm in the testes while females produce their eggs in the ovaries, sperm is nurtured and transported in the ducts until exiting via the penis, females eggs are transported in the uterine tubes to the uterus. The penis delivers sperm to the vagina, which also transports menstrual fluid to the outside and serves as the birth canal. The uterus is where the fertilized egg develops and once the baby is born the breasts provide milk for the baby. The sex hormones are produced by the testes and the ovaries, these have a bug impact on the body; they bring masculinity to males and feminize females. All cells in the body have 46 chromosomes and when mitosis occurs the new cells normally have 46 chromosomes as well. Mitosis being duplication division takes place during growth and for tissue repair. Meiosis being reduction division occurs in the testes during sperm reproduction and in the ovaries for egg reproduction. For meiosis the 46 chromosomes reduce to 23 chromosomes the haploid or n number where as 46 chromosomes are diploid or 2n number. Sperm carries cells to the egg which provides the cytoplasm and chromosomes. The sperm has 23 chromosomes as does the egg, so the zygote which is the first cell of a new human has 46. Cells cannot function without meiosis.
16.2- Male Reproductive System
The scrotum holds the primary sex organs also known as the testes. The tightly coiled ducts known as epididymis is where sperm matures. The vas deferens is where matured sperm go to be stored. From here sperm goes to the ejaculatory ducts, these ducts enter the urethra. The urethra carries semen and urine at different times, therefore urine cannot escape during intercourse. Semen is a fluid containing sperm and secretions from the prostate gland, seminal vesicles and the bulbourethral glands. Semen includes sugar fructose which helps provide energy for the swimming sperm.
Male reproductive system is shown below:
The penis has a long shaft; the enlarged tip at the end is the glans penis. The layer of skin that covers the glans penis is the foreskin which can be surgically removed soon after birth, this is known as circumcision. Erectile tissue extends through the shaft. During sexual arousal the autonomic nerves release NO (nitric oxide); this leads to production of cGMP (cyclic guanosine monophosphate) this allows smooth muscles of the arterial walls to relax and lets erectile tissue fill with blood. The penis becomes erect when the veins become compressed taking blood away from the penis. If the erectile tissue is unable to expand enough for the veins to compress then erectile dysfunction or impotency can occur. Sperm enters the urethra once sexual stimulation intensifies, when the seminal fluid enters the urethra it is released by rhythmic muscle contractions causing it, this is part of the male orgasm. The psychological feeling is in the brain where as the physiological feeling involves the genital organs and body. There can be 400 million sperm in semen when ejaculated.
Sperm and male sex hormones are produced by the testes. During the last 2 months of fetal development the testes drop into the scrotum sacs from inside the abdominal cavity. The testis is made up of lobules- compartments that have 1 to 3 tightly coiled seminiferous tubules, this is packed with cells undergoing sperm production. Spermatogonia divide to make primary spermatocytes that move from the outer wall, get bigger and undergo meiosis I to make secondary spermatocytes. Secondary ones undergo meiosis II to make 4 spermatids, these then differentiate into sperm. Sertoli cells support, nourish and regulate the process of spermatogenesis. A head, middle piece and a tail make up a mature sperm. The middle piece has a mitochondria which gives energy for tail movement or the flagellum. A nucleus covered by the cap known as the acrosome is in the head, here is where enzymes are stored for penetration of the egg. Androgens are the male sex hormones secreted by cells that are between the seminiferous tubules, they are called interstitial cells. Testosterone is the most important androgen.
Testosterone is necessary for normal development and functioning of the sex organs. This brings and maintains the secondary sex characteristics. This provides hair on the face and chest of males. Also helps in greater muscle development.
Hormonal control of testes is shown below:
16.3- Female Reproductive System
The pair of ovaries are female gonads. Eggs and the female sex hormones estrogen and progesterone are produced by the ovaries. From the uterus to the ovaries is the oviducts also known as the uterine or fallopian tubes. The oviducts are not attached to the ovaries, but there are some fimbriae that sweep over them. Fimbriae and cilia are what sweep an egg into the oviduct during ovulation. If an egg is not fertilized it will only live for 6-24 hours. Fertilization begins in the oviduct and goes to the uterus a few days later where implantation occurs and it is embedded in the uterine lining. The uterus is a thick-walled muscular organ. The oviducts are at the upper end while the cervix is at the lower end. Cervix cancer is common in women. A hysterectomy is the removal of uterus and the cervix. The womb is 5 cm wide but can stretch up to 30 cm wide. Formation of the placenta gets help from the lining of the uterus known as the endometrium. 2 layers make up the endometrium- the basal layer and an inner functional layer. When not pregnant the inner layer varies in thickness causing a monthly uterine cycle. The vaginal canal is located at the small opening in the cervix. The acidic environment in the vaginal canal is what protects from pathogenic bacteria.
Female reproductive system
The vulva is an external genital organ, the 2 folds of skin covered with hair included with the vulva are known as the labia majora, the labia minora lay insde the labia majora. The organ involved with sexual arousal is the glans clitoris. The cleft between the labia minora is where the opening to the urethra and the vagina. The hymen (a ring of tissue) is what keeps the vagina somewhat closed until sexual intercourse. When sexual stimulation occurs the labia minora, the vaginal wall and the clitoris become engorged with blood, the breasts swell and the nipples become erect. Also the labia majora enlarge, redden and spread away from the vaginal opening.
16.4- Female Hormone Levels
Ovaries have follicles and they contain immature eggs called oocyte. Females are born with as many as 2 million follicles and when we hit puberty we only have 300,000 to 400,000. Only about 400 follicles ever mature, only 1 egg per month during reproductive years. While the follicle matures it changes from a primary to a secondary to a vesicular follicle. Primary oocytes undergo meiosis I resulting in the cells being haploid with 23 chromosomes. One of these is a polar body which holds discarded chromosomes. If a secondary oocyte is fertilized by sperm it will undergo meiosis II, it not fertilized it won’t undergo anything and will die off. When ovulation occurs the vesicular follicle bursts letting the oocyte go surrounded by a clear membrane. Then the vesicular follicle turns into a corpus luteum, if no egg is fertilized this disintegrates. Primary follicles produce estrogen, secondary produce estrogen and some progesterone. Other progesterone is produced by corpus luteum. Hypothalamus
has control of the sexual function of the ovaries, it secretes gonadotropin releasing hormone.
Estrogen is responsible for secondary sex hormones More fat under the skin is what accounts for females having a more rounded appearance than males. Estrogen and progesterone are essential in breast development. The female pelvis tilting forward is why females tend to have a stomach bulge, protruding buttocks and more of a lower back curve than males. When the ovarian cycle stops it is known as menopause. Complete menopause is when the menstruation cycle is gone for a year. Estrogen and progesterone affect the endometrium which causes the uterus to undergo the cycle. The cycle consists of 28 days, days 1-5 tissue and blood pass through the vagina, days 6-13 the proliferative phase where the endometrium gets thick, on day 14 ovulation occurs. The secretory phase occurs during days 15-28 where the endometrium doubles or triples in thickness. And is now prepared to receive a developing embryo.
The placenta sustains the developing embryo and the fetus. At first the placenta produces human chorionic gonadotropin (HCG), this is what maintains the corpus luteum in the ovary. HCG is what a pregnancy test determines when pregnant. When pregnant the menstruation stops. With birth control pills are taken the active pills build of the uterine lining and when inactive pills are taken the lining sheds and ovulation doesn’t occur. The pills keep the sperm from getting into the uterus by thickening the cervical mucus.
16.5- Control of Reproduction
Not having sex is the most sure way to not get pregnant or to get sexually transmitted diseases. Medications and devices that reduce the chances of getting pregnant are contraceptives. Some forms of contraceptives are IUD- a piece of plastic put into the uterus by a doctor, diaphragm- soft latex cup that fits over the cervix, female condom- a polyurethane tube with a flexible ring that fits in the cervix, male condom- latex sheath that covers the penis. Vasectomy- cutting and sealing the vas deferens, this keeps sperm from reaching the seminal fluid. Tubal ligation- cuts and seals the oviducts which keeps eggs from passing through the oviducts. The morning after pill can be taken after unprotected sex if taken within a certain amount of time to be successful.
If after a year of regular unprotected sex a couple is still unable to become pregnant they are considered infertile. A big reason for males being infertile is due low sperm count or a large amount being abnormal. Smoking and alcohol can contribute to this. And if too much time is spent sitting around the temperature for the testes remains too high for adequate sperm production. In females the highest reason for infertility is body weight. Another cause is pelvic inflammatory disease and endometriosis. Assisted reproductive technologies (ART) are techniques that can help people to become pregnant. There is artificial insemination, where sperm is placed in the vagina by a doctor. In vitro fertilization (IVF) here conception occurs in laboratory glassware. Immature eggs are matured in glassware and then sperm is added, after a few days they are put in uterus and if successful a baby can be born. Gamete intrafallopian transfer- this is the same as the vitro process only this process puts sperm and eggs in the oviducts as soon as they are brought together. Surrogate mothers are being paid and are under contract to carry and have babies. Intracytoplasmic sperm injection is the process of putting a sperm directly in an egg.
16.6- Sexually Transmitted Diseases
Some STDs caused by viruses are HIV infections, genital warts, genital herpes and hepatitis. Genital warts are caused by human papillomaviruses and are associated cervical cancer, tumors of the vulva, anus and penis. Genital herpes are caused by the herpes simplex virus. Type I causes cold sores and fever blisters, type II causes genital herpes. Hepatitis infects the liver which can lead to liver failure, liver cancer and death. Some STDs caused by bacteria are known as chlamydia, gonorrhea and syphilis. Chlamydia can cause cervical ulcerations and have urinary tract infection symptoms. Gonorrhea can lead to pelvic inflammatory disease. Both gonorrhea and chlamydia can lead to infertility. Gonorrhea can spread to internal parts of the body causing heart damage or arthritis. Syphilis can affect the nervous system, a rash can occur and be seen of the bottoms of our hands and feet.
Chapter 17- Development and Aging
17.1- Fertilization
17.2- Pre-Embryonic and Embryonic Development
17.3- Fetal Development
17.4- Pregnancy and Birth
17.5- Development After Birth
17.1- Fertilization
Fertilization occurs when a sperm and an egg unite to form a zygote. The flagellum of a sperm swims to the egg. The zygote gets the cytoplasm and organelles from the mother. The eggs plasma membrane is surrounded by an extracellular matrix called zona pellucida. A few layers of adhering follicular cells known as corona radiata surround the zona pellucida. For fertilization SPERM PENETRATE THE CORONA RADIATA AND ATTEMPT TO PENETRATE THE ZONA PELLUCIDA AND ONLY ONE SPERM ENTERS THE EGG. THE SPERM IS ALLOWED TO PENETRATE THE ZONA PELLUCIDA WITH HELP FROM THE ACROSOME. The zona pelucida and changes in the eggs plasma membrane keep more than one sperm entering an egg. Once a sperm touches the egg the eggs plasma membrane depolarizes to keep other sperm out.
17.2- Pre- Embryonic and Embryonic Development
Cleavage, growth, morphogenesis and differentiation are all processes of development. Extraembryonic membranes are outside of the embryo, these are known as chorion- takes away waste and nourishes the fetus and embryo with oxygen, allantois- accumulates urine produced by fetal kidneys and its blood vessels become the umbilical blood vessels, yolk sac- 1st to appear and is the first site of blood cell formation, amnion- serves as a cushion to protect the embryo.
The extraembryonic membranes are shown below
Pre-embryonic development occurs in the first week. After fertilization the zygote divides over and over as it goes down the oviduct to the uterus. Morula is known as a compacted ball of embryonic cells which become a blastocyst. In this there is an inner cell mass which becomes the embryo, the inner cell mass is surrounded by outer cells which becomes the chorion. Embryonic development begins in the 2nd week lasting until the end of the 2nd month. Implantation is successful when the embryo implants itself in the wall of the uterus. An ectopic pregnancy occurs if the embryo implants itself elsewhere, which will result in an unsuccessful pregnancy. Amniotic fluid serves as an insulator against cold and heat and also absorbs shock. Gastrulation is a major event that moves cells to become tissue layers known as primary germ layers these layers are ectoderm, mesoderm and endoderm. During the 3rd week the nervous system and the heart are relevant. In the 5th week the head enlarges and its possible to make out the eyes, nose and ears. In the 6th-8th weeks the embryo can be recognized as a human, brain development occurs and the embryo is about 38mm long and weighs no more than an aspirin tablet.
17.3- Fetal Development
The placenta is the source of estrogen and progesterone during pregnancy, they have 2 functions- they prevent new follicles from maturing and they maintain the endometrium. The lifeline of the fetus is the umbilical cord, it has the arteries and vein. Fetal development occurs in the 3rd month lasting until the 9th month. In the 3rd and 4th months fingernails, eyebrows, eyelashes, and hair on the head appear. Cartilage is replaced by bone. It is the 3rd month when you can tell the sex of the baby. In the 4th month the heartbat can be heard with a stethoscope. In the 5th through 7th months the mom can feel more than a flutter sensation as the baby can kick and jab when moving around. The eyelids are fully open. At the 8th through 9th months the baby moves so that the head is pointed towards the cervix. If the baby ends up in a breech position (butt 1st) then a c-section may be needed.
The sex of the baby is determined at fertilization. Males have a pair of X and Y chromosomes while females have 2 X chromosomes. Gonads start developing at 7 weeks. Indifferent is what the tissue that gives rise to the gonads. It is called this because it can either be ovaries or testes. At 6 weeks the ducts are the same for males and females. If the SRY gene is present testes will develop and testosterone makes the ducts become male genital ducts. If the SRY gene is not present then ovaries will form instead. With estrogen present female ducts will form. At 14 weeks both the testes and the ovaries are deep inside the abdominal cavity, sperm and follicles are starting to form. The testes descend to the scrotal sac while the ovaries remain in the abdominal cavity.
17.4- Pregnancy and Birth
The energy of a pregnant woman may be lower at first but increase later in the pregnancy. There is a 40% rise in blood volume, with this cardiac output increases 20-30%. Blood flow to the kidneys, placenta, skin, and breasts rises significantly. The uterus pressing on the pelvic cavity can lead to incontinence. Also pregnancy can bring on varicose veins. Stretch marks and pregnancy induced diabetes are other side effects to pregnancy. Throughout pregnancy the uterus contracts lasting 20-30 seconds occurring every 15-20 minutes. Once they last about 40 seconds or longer and occur regularly every 15-20 minutes the woman is in labor. Contractions push the fetus down, stretching the cervix and this happens over and over until birth. In the 1st stage of birth The water breaks and the contractions make the cervical canal disappear as the uterus is pulled up towards the baby’s head. In stage 2 the contractions occur every 1-2 minutes lasting 1 minute each. With this comes the feeling to push as the baby’s head enters the vagina. Once the head and shoulders are out the rest is easy. After the baby is out and breathing ok the umbilical cord is cut and tied. During the 3rd stage the afterbirth is delivered.
17.5- Development After Birth
Infancy, childhood, adolescence and adulthood make up the stages of life. Menopause and andropause are a part of life for men and women. Diabetes type 2 is common in older adults. The immune system in older adults no longer performs as it use to. Some of the hypothesis of aging are that it may have a genetic basis, it may be due to changes that affect the whole body, and it may be due to diet and exercise. With age our skin becomes thinner and we lose some elasticity. Older people feel colder and their skin sags and wrinkles. The leading cause of death is due to cardiovascular disorders. Blood flow to the liver is reduced. The loss of teeth can happen in older adults but not because of aging more because of neglect. All the negativity of aging could be less dramatic if people take care of themselves with eating right and exercising regularly.
Chapter 16- Reproductive System
16.1- Human Life Cycle
16.2- Male Reproductive System
16.3- Female Reproductive System
16.4- Female Hormone Levels
16.5- Control of Reproduction
16.6- Sexually Transmitted Diseases
16.1- Human Life Cycle
The reproductive system for males and females are very different. Puberty is known as a sequence of events that take place for females around the age of 11 and 13 and for males 14 and 16; this is when they become sexually competent young adults. The reproductive system is fully functioning, (ability to produce children) when puberty in complete. In the reproductive system males produce sperm in the testes while females produce their eggs in the ovaries, sperm is nurtured and transported in the ducts until exiting via the penis, females eggs are transported in the uterine tubes to the uterus. The penis delivers sperm to the vagina, which also transports menstrual fluid to the outside and serves as the birth canal. The uterus is where the fertilized egg develops and once the baby is born the breasts provide milk for the baby. The sex hormones are produced by the testes and the ovaries, these have a bug impact on the body; they bring masculinity to males and feminize females. All cells in the body have 46 chromosomes and when mitosis occurs the new cells normally have 46 chromosomes as well. Mitosis being duplication division takes place during growth and for tissue repair. Meiosis being reduction division occurs in the testes during sperm reproduction and in the ovaries for egg reproduction. For meiosis the 46 chromosomes reduce to 23 chromosomes the haploid or n number where as 46 chromosomes are diploid or 2n number. Sperm carries cells to the egg which provides the cytoplasm and chromosomes. The sperm has 23 chromosomes as does the egg, so the zygote which is the first cell of a new human has 46. Cells cannot function without meiosis.
16.2- Male Reproductive System
The scrotum holds the primary sex organs also known as the testes. The tightly coiled ducts known as epididymis is where sperm matures. The vas deferens is where matured sperm go to be stored. From here sperm goes to the ejaculatory ducts, these ducts enter the urethra. The urethra carries semen and urine at different times, therefore urine cannot escape during intercourse. Semen is a fluid containing sperm and secretions from the prostate gland, seminal vesicles and the bulbourethral glands. Semen includes sugar fructose which helps provide energy for the swimming sperm.
Male reproductive system is shown below:
The penis has a long shaft; the enlarged tip at the end is the glans penis. The layer of skin that covers the glans penis is the foreskin which can be surgically removed soon after birth, this is known as circumcision. Erectile tissue extends through the shaft. During sexual arousal the autonomic nerves release NO (nitric oxide); this leads to production of cGMP (cyclic guanosine monophosphate) this allows smooth muscles of the arterial walls to relax and lets erectile tissue fill with blood. The penis becomes erect when the veins become compressed taking blood away from the penis. If the erectile tissue is unable to expand enough for the veins to compress then erectile dysfunction or impotency can occur. Sperm enters the urethra once sexual stimulation intensifies, when the seminal fluid enters the urethra it is released by rhythmic muscle contractions causing it, this is part of the male orgasm. The psychological feeling is in the brain where as the physiological feeling involves the genital organs and body. There can be 400 million sperm in semen when ejaculated.
Sperm and male sex hormones are produced by the testes. During the last 2 months of fetal development the testes drop into the scrotum sacs from inside the abdominal cavity. The testis is made up of lobules- compartments that have 1 to 3 tightly coiled seminiferous tubules, this is packed with cells undergoing sperm production. Spermatogonia divide to make primary spermatocytes that move from the outer wall, get bigger and undergo meiosis I to make secondary spermatocytes. Secondary ones undergo meiosis II to make 4 spermatids, these then differentiate into sperm. Sertoli cells support, nourish and regulate the process of spermatogenesis. A head, middle piece and a tail make up a mature sperm. The middle piece has a mitochondria which gives energy for tail movement or the flagellum. A nucleus covered by the cap known as the acrosome is in the head, here is where enzymes are stored for penetration of the egg. Androgens are the male sex hormones secreted by cells that are between the seminiferous tubules, they are called interstitial cells. Testosterone is the most important androgen.
Testosterone is necessary for normal development and functioning of the sex organs. This brings and maintains the secondary sex characteristics. This provides hair on the face and chest of males. Also helps in greater muscle development.
Hormonal control of testes is shown below:
16.3- Female Reproductive System
The pair of ovaries are female gonads. Eggs and the female sex hormones estrogen and progesterone are produced by the ovaries. From the uterus to the ovaries is the oviducts also known as the uterine or fallopian tubes. The oviducts are not attached to the ovaries, but there are some fimbriae that sweep over them. Fimbriae and cilia are what sweep an egg into the oviduct during ovulation. If an egg is not fertilized it will only live for 6-24 hours. Fertilization begins in the oviduct and goes to the uterus a few days later where implantation occurs and it is embedded in the uterine lining. The uterus is a thick-walled muscular organ. The oviducts are at the upper end while the cervix is at the lower end. Cervix cancer is common in women. A hysterectomy is the removal of uterus and the cervix. The womb is 5 cm wide but can stretch up to 30 cm wide. Formation of the placenta gets help from the lining of the uterus known as the endometrium. 2 layers make up the endometrium- the basal layer and an inner functional layer. When not pregnant the inner layer varies in thickness causing a monthly uterine cycle. The vaginal canal is located at the small opening in the cervix. The acidic environment in the vaginal canal is what protects from pathogenic bacteria.
Female reproductive system
The vulva is an external genital organ, the 2 folds of skin covered with hair included with the vulva are known as the labia majora, the labia minora lay insde the labia majora. The organ involved with sexual arousal is the glans clitoris. The cleft between the labia minora is where the opening to the urethra and the vagina. The hymen (a ring of tissue) is what keeps the vagina somewhat closed until sexual intercourse. When sexual stimulation occurs the labia minora, the vaginal wall and the clitoris become engorged with blood, the breasts swell and the nipples become erect. Also the labia majora enlarge, redden and spread away from the vaginal opening.
16.4- Female Hormone Levels
Ovaries have follicles and they contain immature eggs called oocyte. Females are born with as many as 2 million follicles and when we hit puberty we only have 300,000 to 400,000. Only about 400 follicles ever mature, only 1 egg per month during reproductive years. While the follicle matures it changes from a primary to a secondary to a vesicular follicle. Primary oocytes undergo meiosis I resulting in the cells being haploid with 23 chromosomes. One of these is a polar body which holds discarded chromosomes. If a secondary oocyte is fertilized by sperm it will undergo meiosis II, it not fertilized it won’t undergo anything and will die off. When ovulation occurs the vesicular follicle bursts letting the oocyte go surrounded by a clear membrane. Then the vesicular follicle turns into a corpus luteum, if no egg is fertilized this disintegrates. Primary follicles produce estrogen, secondary produce estrogen and some progesterone. Other progesterone is produced by corpus luteum. Hypothalamus
has control of the sexual function of the ovaries, it secretes gonadotropin releasing hormone.
Estrogen is responsible for secondary sex hormones More fat under the skin is what accounts for females having a more rounded appearance than males. Estrogen and progesterone are essential in breast development. The female pelvis tilting forward is why females tend to have a stomach bulge, protruding buttocks and more of a lower back curve than males. When the ovarian cycle stops it is known as menopause. Complete menopause is when the menstruation cycle is gone for a year. Estrogen and progesterone affect the endometrium which causes the uterus to undergo the cycle. The cycle consists of 28 days, days 1-5 tissue and blood pass through the vagina, days 6-13 the proliferative phase where the endometrium gets thick, on day 14 ovulation occurs. The secretory phase occurs during days 15-28 where the endometrium doubles or triples in thickness. And is now prepared to receive a developing embryo.
The placenta sustains the developing embryo and the fetus. At first the placenta produces human chorionic gonadotropin (HCG), this is what maintains the corpus luteum in the ovary. HCG is what a pregnancy test determines when pregnant. When pregnant the menstruation stops. With birth control pills are taken the active pills build of the uterine lining and when inactive pills are taken the lining sheds and ovulation doesn’t occur. The pills keep the sperm from getting into the uterus by thickening the cervical mucus.
16.5- Control of Reproduction
Not having sex is the most sure way to not get pregnant or to get sexually transmitted diseases. Medications and devices that reduce the chances of getting pregnant are contraceptives. Some forms of contraceptives are IUD- a piece of plastic put into the uterus by a doctor, diaphragm- soft latex cup that fits over the cervix, female condom- a polyurethane tube with a flexible ring that fits in the cervix, male condom- latex sheath that covers the penis. Vasectomy- cutting and sealing the vas deferens, this keeps sperm from reaching the seminal fluid. Tubal ligation- cuts and seals the oviducts which keeps eggs from passing through the oviducts. The morning after pill can be taken after unprotected sex if taken within a certain amount of time to be successful.
If after a year of regular unprotected sex a couple is still unable to become pregnant they are considered infertile. A big reason for males being infertile is due low sperm count or a large amount being abnormal. Smoking and alcohol can contribute to this. And if too much time is spent sitting around the temperature for the testes remains too high for adequate sperm production. In females the highest reason for infertility is body weight. Another cause is pelvic inflammatory disease and endometriosis. Assisted reproductive technologies (ART) are techniques that can help people to become pregnant. There is artificial insemination, where sperm is placed in the vagina by a doctor. In vitro fertilization (IVF) here conception occurs in laboratory glassware. Immature eggs are matured in glassware and then sperm is added, after a few days they are put in uterus and if successful a baby can be born. Gamete intrafallopian transfer- this is the same as the vitro process only this process puts sperm and eggs in the oviducts as soon as they are brought together. Surrogate mothers are being paid and are under contract to carry and have babies. Intracytoplasmic sperm injection is the process of putting a sperm directly in an egg.
16.6- Sexually Transmitted Diseases
Some STDs caused by viruses are HIV infections, genital warts, genital herpes and hepatitis. Genital warts are caused by human papillomaviruses and are associated cervical cancer, tumors of the vulva, anus and penis. Genital herpes are caused by the herpes simplex virus. Type I causes cold sores and fever blisters, type II causes genital herpes. Hepatitis infects the liver which can lead to liver failure, liver cancer and death. Some STDs caused by bacteria are known as chlamydia, gonorrhea and syphilis. Chlamydia can cause cervical ulcerations and have urinary tract infection symptoms. Gonorrhea can lead to pelvic inflammatory disease. Both gonorrhea and chlamydia can lead to infertility. Gonorrhea can spread to internal parts of the body causing heart damage or arthritis. Syphilis can affect the nervous system, a rash can occur and be seen of the bottoms of our hands and feet.
Chapter 17- Development and Aging
17.1- Fertilization
17.2- Pre-Embryonic and Embryonic Development
17.3- Fetal Development
17.4- Pregnancy and Birth
17.5- Development After Birth
17.1- Fertilization
Fertilization occurs when a sperm and an egg unite to form a zygote. The flagellum of a sperm swims to the egg. The zygote gets the cytoplasm and organelles from the mother. The eggs plasma membrane is surrounded by an extracellular matrix called zona pellucida. A few layers of adhering follicular cells known as corona radiata surround the zona pellucida. For fertilization SPERM PENETRATE THE CORONA RADIATA AND ATTEMPT TO PENETRATE THE ZONA PELLUCIDA AND ONLY ONE SPERM ENTERS THE EGG. THE SPERM IS ALLOWED TO PENETRATE THE ZONA PELLUCIDA WITH HELP FROM THE ACROSOME. The zona pelucida and changes in the eggs plasma membrane keep more than one sperm entering an egg. Once a sperm touches the egg the eggs plasma membrane depolarizes to keep other sperm out.
17.2- Pre- Embryonic and Embryonic Development
Cleavage, growth, morphogenesis and differentiation are all processes of development. Extraembryonic membranes are outside of the embryo, these are known as chorion- takes away waste and nourishes the fetus and embryo with oxygen, allantois- accumulates urine produced by fetal kidneys and its blood vessels become the umbilical blood vessels, yolk sac- 1st to appear and is the first site of blood cell formation, amnion- serves as a cushion to protect the embryo.
The extraembryonic membranes are shown below
Pre-embryonic development occurs in the first week. After fertilization the zygote divides over and over as it goes down the oviduct to the uterus. Morula is known as a compacted ball of embryonic cells which become a blastocyst. In this there is an inner cell mass which becomes the embryo, the inner cell mass is surrounded by outer cells which becomes the chorion. Embryonic development begins in the 2nd week lasting until the end of the 2nd month. Implantation is successful when the embryo implants itself in the wall of the uterus. An ectopic pregnancy occurs if the embryo implants itself elsewhere, which will result in an unsuccessful pregnancy. Amniotic fluid serves as an insulator against cold and heat and also absorbs shock. Gastrulation is a major event that moves cells to become tissue layers known as primary germ layers these layers are ectoderm, mesoderm and endoderm. During the 3rd week the nervous system and the heart are relevant. In the 5th week the head enlarges and its possible to make out the eyes, nose and ears. In the 6th-8th weeks the embryo can be recognized as a human, brain development occurs and the embryo is about 38mm long and weighs no more than an aspirin tablet.
17.3- Fetal Development
The placenta is the source of estrogen and progesterone during pregnancy, they have 2 functions- they prevent new follicles from maturing and they maintain the endometrium. The lifeline of the fetus is the umbilical cord, it has the arteries and vein. Fetal development occurs in the 3rd month lasting until the 9th month. In the 3rd and 4th months fingernails, eyebrows, eyelashes, and hair on the head appear. Cartilage is replaced by bone. It is the 3rd month when you can tell the sex of the baby. In the 4th month the heartbat can be heard with a stethoscope. In the 5th through 7th months the mom can feel more than a flutter sensation as the baby can kick and jab when moving around. The eyelids are fully open. At the 8th through 9th months the baby moves so that the head is pointed towards the cervix. If the baby ends up in a breech position (butt 1st) then a c-section may be needed.
The sex of the baby is determined at fertilization. Males have a pair of X and Y chromosomes while females have 2 X chromosomes. Gonads start developing at 7 weeks. Indifferent is what the tissue that gives rise to the gonads. It is called this because it can either be ovaries or testes. At 6 weeks the ducts are the same for males and females. If the SRY gene is present testes will develop and testosterone makes the ducts become male genital ducts. If the SRY gene is not present then ovaries will form instead. With estrogen present female ducts will form. At 14 weeks both the testes and the ovaries are deep inside the abdominal cavity, sperm and follicles are starting to form. The testes descend to the scrotal sac while the ovaries remain in the abdominal cavity.
17.4- Pregnancy and Birth
The energy of a pregnant woman may be lower at first but increase later in the pregnancy. There is a 40% rise in blood volume, with this cardiac output increases 20-30%. Blood flow to the kidneys, placenta, skin, and breasts rises significantly. The uterus pressing on the pelvic cavity can lead to incontinence. Also pregnancy can bring on varicose veins. Stretch marks and pregnancy induced diabetes are other side effects to pregnancy. Throughout pregnancy the uterus contracts lasting 20-30 seconds occurring every 15-20 minutes. Once they last about 40 seconds or longer and occur regularly every 15-20 minutes the woman is in labor. Contractions push the fetus down, stretching the cervix and this happens over and over until birth. In the 1st stage of birth The water breaks and the contractions make the cervical canal disappear as the uterus is pulled up towards the baby’s head. In stage 2 the contractions occur every 1-2 minutes lasting 1 minute each. With this comes the feeling to push as the baby’s head enters the vagina. Once the head and shoulders are out the rest is easy. After the baby is out and breathing ok the umbilical cord is cut and tied. During the 3rd stage the afterbirth is delivered.
17.5- Development After Birth
Infancy, childhood, adolescence and adulthood make up the stages of life. Menopause and andropause are a part of life for men and women. Diabetes type 2 is common in older adults. The immune system in older adults no longer performs as it use to. Some of the hypothesis of aging are that it may have a genetic basis, it may be due to changes that affect the whole body, and it may be due to diet and exercise. With age our skin becomes thinner and we lose some elasticity. Older people feel colder and their skin sags and wrinkles. The leading cause of death is due to cardiovascular disorders. Blood flow to the liver is reduced. The loss of teeth can happen in older adults but not because of aging more because of neglect. All the negativity of aging could be less dramatic if people take care of themselves with eating right and exercising regularly.
Friday, November 14, 2008
Compendium Review Unit 3/ Topic 2- Movement
Compendium Review- Unit 3- Environmental Interactions- Topic 2-Movement
Chapter 11- Skeletal System
11.1- Overview of Skeletal System
11.2- Bone Growth, Remodeling, and Repair
11.3- Bones of the Axial Skeleton
11.4- Bones of the Appendicular Skeleton
11.5- Articulations
11.1- Overview of Skeletal System
There are 206 bones in the adult body. The skeleton is what supports the body, produces blood cells, protects soft body parts, stores minerals and fat, and permits flexible body movement. The main part of the bone is the diaphysis which has a medullary cavity that’s walls are composed of compact bone. The cavity is filled with yellow bone marrow that stores fat. The part of the bone that’s at the end of a long bone is the epiphyses which is made of spongy bone that has red bone marrow, where blood cells are made. Articular cartilage occurs at a joint. Periosteum is the connective tissue that covers the long bone, besides at the ends. Osteons are the tubular units that make up compact bone. Osteocytes are the bone cells that pass on nutrients and collect wastes from other cells. Spongy bone has thin plates separated by unequal space, this bone is better for strength. Red bone marrow is what fills the spaces in spongy bone. Cartilage is gel like, has no nerves and makes good padding for joints. Cartilage doesn’t heal fast because it has no blood vessels. There are three types- Hyaline cartilage- firm and flexible, Fibrocartilage- stronger, withholds tension and pressure and elastic cartilage- more flexible than hyaline cartilage. Fibrous connective tissue makes up ligaments and tendons.
Anatomy of a long bone shown below:
11.2- Bone Growth, Remodeling, and Repair
Some bones grow in length and width through adolescence but some continue until the age of 25, at six weeks the embryo skeleton starts to form. Some cells that help in bone growth, remodeling and repair are osteoblasts, osteocytes, and osteoclasts. Osteoclasts remove matrix from the bone and osteoblasts build it up, these turn in to osteocytes when surrounded by calcified matix. Formation of the bone is known as ossification. Intramembranous ossification are bones that develop between sheets of fibrous connective tissue. Endochondral ossification is what most of the bones of the skeleton are formed by. The growth plate or the epiphyseal plate is a band of cartilage. Four layers make up the plate, layer closest to the plate is the resting zone where cartilage remains. Next is the proliferating zone where chondrocytes produce new cartilage cells. Third layer is the degenerating zone where the cartilage cells die and the final layer is the ossification zone where bone is forming (this is what makes the bone length increase.) Hormones are chemical messengers that act on different parts of the body that have an affect on bone growth. Growth hormone (GH) is what stimulates bones growth, too little can lead to being a dwarf and too much can lead to being a giant.
Bone remodeling is the process of bone renewal, 18% of bone is recycled each year. This process keeps bones strong and the recycling helps the body to regulate the amount of calcium in the blood. The parathyroid hormone and calcitonin hormone help to regulate this level. Parathyroid speeds up bone recycling and calcitonin acts opposite of that.
After a bone suffers a break or fracture a repair is needed. There are four steps for a fracture repair that takes place during a few months 1- hematoma which is a mass where blood escapes from a ruptured blood vessel after a fracture, 2- fibrocartilaginous callus which is where tissue repair begins, 3- bony callus which joins the broken bones together and 4- remodeling spongy bone is absorbed and compact bone is built.
Bone fracture and repair shown below
11.3- Bones of the Axial Skeleton
The axial skeleton is in the midline of the body consisting of the skull, hyoid bone, vertebral column and the rib cage. The braincase and facial bones form the skull. Eight bones make up the cranium or braincase. Major bones of the cranium are the frontal bone- forms the forehead, parietal bones- extend to the sides, occipital bone- curves to form the base of the skull and the foramen magnum- where the spinal cord passes and becomes the brain stem. The temporal bone leads to the middle ear. Sphenoid bone is the keystone of cranial bones- all other bones articulate with it. This bon makes the eye sockets and sides of the skull. Lower jaw bone is the mandible an is the only moveable bone of the skull. Tooth sockets are located here and on the maxillae- the bones that form the upper jaw. Zygomatic bones are the cheekbone prominences and the nasal bones make the bridge of the nose. The only bone in the body that does not articulate with another bone is known as the hyoid bone, which is part of the axial skeleton but not the skull.
33 vertebrae make up the vertebral column. Four curves of the column provide strength and resilience. When vertebrae join the column is formed. Spinal nerves control skeletal muscle contractions. Cervical vertebrae are in the neck, first one is the atlas which holds up the neck. Second one is the axis which allows the rotation of the neck. Intervertebral disks are in between the vertebrae and act as padding. The disks help us bend either way and move side to side.
Thoracic vertebrae make up the rib cage which is part of the axial skeleton. The rib cage protects the heart and lungs. Flattened bones make up the ribs, there are twelve pairs connected to the thoracic vertebrae in the back. The top seven pairs connect to the sternum by way costal cartilage, known as true ribs. Next three pairs are false ribs, they connect to the sternum by way of common cartilage. Last two pairs are floating ribs because they don’t attach to the sternum, they attach to the vertebrae T12. Midline of the body is the sternum, which also helps protect the lungs and the heart. Three bones make up the sternum the manubrium, the body, and the xiphoid process. Manubrium occurs at the level of the second rib which allows the ribs to be counted. Apex of the heart is located between the fifth and sixth ribs.
11.4- Bones of the Appendicular Skeleton
Bones of the pectoral and pelvic girdles and the attached limbs make up the appendicular skeleton. Pectoral girdles are on both side of the body and are made up of a scapula and a clavicle. Clavicle goes across the top of the thorax, scapula is a visible bone in he back. Rotator cuff is made of tendons extending to the humerus from four small muscles. Eight carpal bones make up the wrist, five metacarpal bones form the palm. Phalanges are the finger and thumb bones.
Hip bones make up the pelvic girdle. The pelvis bears the weight of the body, protects organs with the pelvic cavity and is what attaches the legs. Three parts make up the coxal bone, the ilium, ischium, and the pubis. Hip socket occurs where these three meet. Ilium is the largest part. Ischium is what we sit on. Pubic bone is the anterior part of the coxal bone. Thighbone is known as the femur and is the longest and strongest bone in the body. Tibia is the region of the knee and kneecap. Quadriceps tendon is what holds the kneecap in place. Slender bone in the leg is the fibula, forms at the outer bulge of the ankle. Seven tarsal bones make up the ankle, one of these the talus, can move freely where it joins the tibula and fibula. Heel bone is known as the calcaneus is considered part of the ankle. This and the talus support the weight of our bodies.
11.5- Articulations
Bones joined at the joints are classified as fibrous cartilaginous. Fibrous joints like the sutures in between the cranial bones are immoveable. Hyaline cartilage is what connects the cartilaginous joints. These joints are slightly moveable. Synovial fluid fills the synovial joint which is freely moveable. This fluid is a lubricant for the joint.
Synovial joints shown below:
Ball and socket joints at the hips and the shoulders allow movement in all planes. Elbow and knee joints are synovial joint known as hinge joints, they allow movement only one way. Tendons are what attach intact skeletal muscles to bones.
Chapter 12- Muscular System
12.1- Overview of Muscular System
12.2- Skeletal Muscle Fiber Contraction
12.3- Whole Muscle Contraction
12.4- Muscular Disorders
12.5- Homeostasis
12.1- Overview of Muscular System
There are three types of muscle tissue first there is smooth muscle which has muscle fibers that are spindle shaped cells and is located in the walls of the hollow internal organs. Contraction of this muscle in involuntary. Second type is cardiac muscle which forms the heart walls. This muscle contracting is involuntary as well. Last there is the skeletal muscle which can be long. This type of muscle is voluntary. This muscle supports the body, helps keep a regular body temperature, is responsible for making the body move, and this muscle keeps blood moving through the cardiovascular veins and lymph moving through lymphatic vessels. Skeletal muscles also assist in keeping internal organs safe and joints stabilized.
Fascicles are skeletal muscle fibers that make up a whole muscle. Connective tissue surrounds the fascicles inside and out. Tendons are the fascia, a connective tissue that covers muscles that extend beyond the muscles. Tendons anchor muscles to bones. Muscles contract-pulling on the tendon-bone moves. Muscles work in pairs but the one that does most of the work in known as the prime mover. Synergists are the muscles that help the prime mover. Muscles pull not push, they become shorter when contracted. Antagonist are the muscles that work opposite the prime mover.
12.2- Skeletal Muscle Fiber Contraction
The plasma membrane for muscle fibers is known as sarcolemma, cytoplasm known as sarcoplasmic reticulum. Myofibrils are in the reticulum and are the contractile portions of a muscle. Sarcomeres are the units responsible for muscle contraction. Two protein myofilaments myosin and actin make up sarcomeres. Myosin is thick filament while actin is thin filament. When a muscle contraction occurs sarcomeres shorten allowing actin filaments to slide past myosin filaments. Energy for muscle contraction is supplied by ATP. Myosin does the work, it breaks down ATP. Motor neurons are what stimulate contraction in muscle fiber. ACh fills synaptic vesicles in axon terminals. ACh is release when nerve impulses moving down a motor neuron arrive at the axon terminal. Once it is released it diffuses across the cleft and binds to receptors in the sarcolemma. Calcium being released from the reticulum leads to sarcomere contraction. Tropomyosin is a protein that winds about an actin filament while troponin, another protein occurs along the threads. Myosin can bind to actin when calcium is released and combines with troponin.
12.3- Whole Muscle Contraction
Motor units are made up of nerve fiber and muscle fiber. The all or none law is what motor units go by, once a motor unit is stimulated they either all contract or not. Muscle twitches are a response to infrequent electrical impulses. Three stages make up a twitch, first the latent period which is the time between stimulation and initiation of the contraction, next the contraction period, shortening of the muscle and last the relaxation period which is the muscle going back to the previous length. Tetanus is maximal sustained contraction and continues until the muscle fatigues. Sustained contractions occur when some motor units contract maximally while others are resting to keep all muscles from fatiguing at once. Four types of energy sources for muscles are muscle triglycerides, plasma fatty acids, blood glucose and muscle glycogen. Glycogen and triglycerides are stored in muscle the other two come from blood. A limited amount of ATP is stored in muscle cells and if more is needed they can get it from formation of ATP by creatine phosphate pathway, formation of ATP by fermentation and/or formation of ATP cellular respiration.
Slow twitch fibers prefer cellular respiration while fast twitch prefer fermentation and creatine phosphate pathway for ATP. Fast twitch muscle fibers are anaerobic, fatigue easily and have huge power. Slow twitch is aerobic, has steady power and endurance. Delayed onset muscle soreness can occur 24-48 hours after hard exercise. This can be avoided with stretching before exercising and when starting something new to take it slow building up your strength and endurance avoiding straining yourself.
12.4- Muscular Disorders
Sudden and involuntary muscle contractions that can sometimes be painful are known as spasms. If this occurs in the intestinal tract a bellyache can occur. If these come in multiples then seizures or convulsions can result. Long painful spasms are known as cramps. With a lot of effort a person can control facial tics. If a muscle is stretched or torn a strain can occur. If a joint is twisted a sprain can occur. If a tendon becomes injured or inflamed movement of a joint can be painful and tendonitis can result. Myalgia and fibromyalgia are two types of muscular diseases. Myalgia can result from overstretching or overworking muscles or can come from viral infections. The result is achy muscles. Fibromyalgia is chronic and causes achy pain, tenderness and stiffness of muscles. A progression of degenerating and weakening muscles is muscular dystrophy. Lou Gehrig’s disease has no cure and causes the inability to chew, talk, walk and swallow.
12.5- Homeostasis
Skeletal and muscular systems work together in maintain homeostasis, one assists the other with eating and moving, keeping the heart pumping, and breathing. While the skeletal system protects the soft organs the muscular system protects the abdominal organs. The skeletal system produces red bone marrow and regulates blood calcium while the muscular system helps regulate the body temperature, keeping it stable.
Chapter 11- Skeletal System
11.1- Overview of Skeletal System
11.2- Bone Growth, Remodeling, and Repair
11.3- Bones of the Axial Skeleton
11.4- Bones of the Appendicular Skeleton
11.5- Articulations
11.1- Overview of Skeletal System
There are 206 bones in the adult body. The skeleton is what supports the body, produces blood cells, protects soft body parts, stores minerals and fat, and permits flexible body movement. The main part of the bone is the diaphysis which has a medullary cavity that’s walls are composed of compact bone. The cavity is filled with yellow bone marrow that stores fat. The part of the bone that’s at the end of a long bone is the epiphyses which is made of spongy bone that has red bone marrow, where blood cells are made. Articular cartilage occurs at a joint. Periosteum is the connective tissue that covers the long bone, besides at the ends. Osteons are the tubular units that make up compact bone. Osteocytes are the bone cells that pass on nutrients and collect wastes from other cells. Spongy bone has thin plates separated by unequal space, this bone is better for strength. Red bone marrow is what fills the spaces in spongy bone. Cartilage is gel like, has no nerves and makes good padding for joints. Cartilage doesn’t heal fast because it has no blood vessels. There are three types- Hyaline cartilage- firm and flexible, Fibrocartilage- stronger, withholds tension and pressure and elastic cartilage- more flexible than hyaline cartilage. Fibrous connective tissue makes up ligaments and tendons.
Anatomy of a long bone shown below:
11.2- Bone Growth, Remodeling, and Repair
Some bones grow in length and width through adolescence but some continue until the age of 25, at six weeks the embryo skeleton starts to form. Some cells that help in bone growth, remodeling and repair are osteoblasts, osteocytes, and osteoclasts. Osteoclasts remove matrix from the bone and osteoblasts build it up, these turn in to osteocytes when surrounded by calcified matix. Formation of the bone is known as ossification. Intramembranous ossification are bones that develop between sheets of fibrous connective tissue. Endochondral ossification is what most of the bones of the skeleton are formed by. The growth plate or the epiphyseal plate is a band of cartilage. Four layers make up the plate, layer closest to the plate is the resting zone where cartilage remains. Next is the proliferating zone where chondrocytes produce new cartilage cells. Third layer is the degenerating zone where the cartilage cells die and the final layer is the ossification zone where bone is forming (this is what makes the bone length increase.) Hormones are chemical messengers that act on different parts of the body that have an affect on bone growth. Growth hormone (GH) is what stimulates bones growth, too little can lead to being a dwarf and too much can lead to being a giant.
Bone remodeling is the process of bone renewal, 18% of bone is recycled each year. This process keeps bones strong and the recycling helps the body to regulate the amount of calcium in the blood. The parathyroid hormone and calcitonin hormone help to regulate this level. Parathyroid speeds up bone recycling and calcitonin acts opposite of that.
After a bone suffers a break or fracture a repair is needed. There are four steps for a fracture repair that takes place during a few months 1- hematoma which is a mass where blood escapes from a ruptured blood vessel after a fracture, 2- fibrocartilaginous callus which is where tissue repair begins, 3- bony callus which joins the broken bones together and 4- remodeling spongy bone is absorbed and compact bone is built.
Bone fracture and repair shown below
11.3- Bones of the Axial Skeleton
The axial skeleton is in the midline of the body consisting of the skull, hyoid bone, vertebral column and the rib cage. The braincase and facial bones form the skull. Eight bones make up the cranium or braincase. Major bones of the cranium are the frontal bone- forms the forehead, parietal bones- extend to the sides, occipital bone- curves to form the base of the skull and the foramen magnum- where the spinal cord passes and becomes the brain stem. The temporal bone leads to the middle ear. Sphenoid bone is the keystone of cranial bones- all other bones articulate with it. This bon makes the eye sockets and sides of the skull. Lower jaw bone is the mandible an is the only moveable bone of the skull. Tooth sockets are located here and on the maxillae- the bones that form the upper jaw. Zygomatic bones are the cheekbone prominences and the nasal bones make the bridge of the nose. The only bone in the body that does not articulate with another bone is known as the hyoid bone, which is part of the axial skeleton but not the skull.
33 vertebrae make up the vertebral column. Four curves of the column provide strength and resilience. When vertebrae join the column is formed. Spinal nerves control skeletal muscle contractions. Cervical vertebrae are in the neck, first one is the atlas which holds up the neck. Second one is the axis which allows the rotation of the neck. Intervertebral disks are in between the vertebrae and act as padding. The disks help us bend either way and move side to side.
Thoracic vertebrae make up the rib cage which is part of the axial skeleton. The rib cage protects the heart and lungs. Flattened bones make up the ribs, there are twelve pairs connected to the thoracic vertebrae in the back. The top seven pairs connect to the sternum by way costal cartilage, known as true ribs. Next three pairs are false ribs, they connect to the sternum by way of common cartilage. Last two pairs are floating ribs because they don’t attach to the sternum, they attach to the vertebrae T12. Midline of the body is the sternum, which also helps protect the lungs and the heart. Three bones make up the sternum the manubrium, the body, and the xiphoid process. Manubrium occurs at the level of the second rib which allows the ribs to be counted. Apex of the heart is located between the fifth and sixth ribs.
11.4- Bones of the Appendicular Skeleton
Bones of the pectoral and pelvic girdles and the attached limbs make up the appendicular skeleton. Pectoral girdles are on both side of the body and are made up of a scapula and a clavicle. Clavicle goes across the top of the thorax, scapula is a visible bone in he back. Rotator cuff is made of tendons extending to the humerus from four small muscles. Eight carpal bones make up the wrist, five metacarpal bones form the palm. Phalanges are the finger and thumb bones.
Hip bones make up the pelvic girdle. The pelvis bears the weight of the body, protects organs with the pelvic cavity and is what attaches the legs. Three parts make up the coxal bone, the ilium, ischium, and the pubis. Hip socket occurs where these three meet. Ilium is the largest part. Ischium is what we sit on. Pubic bone is the anterior part of the coxal bone. Thighbone is known as the femur and is the longest and strongest bone in the body. Tibia is the region of the knee and kneecap. Quadriceps tendon is what holds the kneecap in place. Slender bone in the leg is the fibula, forms at the outer bulge of the ankle. Seven tarsal bones make up the ankle, one of these the talus, can move freely where it joins the tibula and fibula. Heel bone is known as the calcaneus is considered part of the ankle. This and the talus support the weight of our bodies.
11.5- Articulations
Bones joined at the joints are classified as fibrous cartilaginous. Fibrous joints like the sutures in between the cranial bones are immoveable. Hyaline cartilage is what connects the cartilaginous joints. These joints are slightly moveable. Synovial fluid fills the synovial joint which is freely moveable. This fluid is a lubricant for the joint.
Synovial joints shown below:
Ball and socket joints at the hips and the shoulders allow movement in all planes. Elbow and knee joints are synovial joint known as hinge joints, they allow movement only one way. Tendons are what attach intact skeletal muscles to bones.
Chapter 12- Muscular System
12.1- Overview of Muscular System
12.2- Skeletal Muscle Fiber Contraction
12.3- Whole Muscle Contraction
12.4- Muscular Disorders
12.5- Homeostasis
12.1- Overview of Muscular System
There are three types of muscle tissue first there is smooth muscle which has muscle fibers that are spindle shaped cells and is located in the walls of the hollow internal organs. Contraction of this muscle in involuntary. Second type is cardiac muscle which forms the heart walls. This muscle contracting is involuntary as well. Last there is the skeletal muscle which can be long. This type of muscle is voluntary. This muscle supports the body, helps keep a regular body temperature, is responsible for making the body move, and this muscle keeps blood moving through the cardiovascular veins and lymph moving through lymphatic vessels. Skeletal muscles also assist in keeping internal organs safe and joints stabilized.
Fascicles are skeletal muscle fibers that make up a whole muscle. Connective tissue surrounds the fascicles inside and out. Tendons are the fascia, a connective tissue that covers muscles that extend beyond the muscles. Tendons anchor muscles to bones. Muscles contract-pulling on the tendon-bone moves. Muscles work in pairs but the one that does most of the work in known as the prime mover. Synergists are the muscles that help the prime mover. Muscles pull not push, they become shorter when contracted. Antagonist are the muscles that work opposite the prime mover.
12.2- Skeletal Muscle Fiber Contraction
The plasma membrane for muscle fibers is known as sarcolemma, cytoplasm known as sarcoplasmic reticulum. Myofibrils are in the reticulum and are the contractile portions of a muscle. Sarcomeres are the units responsible for muscle contraction. Two protein myofilaments myosin and actin make up sarcomeres. Myosin is thick filament while actin is thin filament. When a muscle contraction occurs sarcomeres shorten allowing actin filaments to slide past myosin filaments. Energy for muscle contraction is supplied by ATP. Myosin does the work, it breaks down ATP. Motor neurons are what stimulate contraction in muscle fiber. ACh fills synaptic vesicles in axon terminals. ACh is release when nerve impulses moving down a motor neuron arrive at the axon terminal. Once it is released it diffuses across the cleft and binds to receptors in the sarcolemma. Calcium being released from the reticulum leads to sarcomere contraction. Tropomyosin is a protein that winds about an actin filament while troponin, another protein occurs along the threads. Myosin can bind to actin when calcium is released and combines with troponin.
12.3- Whole Muscle Contraction
Motor units are made up of nerve fiber and muscle fiber. The all or none law is what motor units go by, once a motor unit is stimulated they either all contract or not. Muscle twitches are a response to infrequent electrical impulses. Three stages make up a twitch, first the latent period which is the time between stimulation and initiation of the contraction, next the contraction period, shortening of the muscle and last the relaxation period which is the muscle going back to the previous length. Tetanus is maximal sustained contraction and continues until the muscle fatigues. Sustained contractions occur when some motor units contract maximally while others are resting to keep all muscles from fatiguing at once. Four types of energy sources for muscles are muscle triglycerides, plasma fatty acids, blood glucose and muscle glycogen. Glycogen and triglycerides are stored in muscle the other two come from blood. A limited amount of ATP is stored in muscle cells and if more is needed they can get it from formation of ATP by creatine phosphate pathway, formation of ATP by fermentation and/or formation of ATP cellular respiration.
Slow twitch fibers prefer cellular respiration while fast twitch prefer fermentation and creatine phosphate pathway for ATP. Fast twitch muscle fibers are anaerobic, fatigue easily and have huge power. Slow twitch is aerobic, has steady power and endurance. Delayed onset muscle soreness can occur 24-48 hours after hard exercise. This can be avoided with stretching before exercising and when starting something new to take it slow building up your strength and endurance avoiding straining yourself.
12.4- Muscular Disorders
Sudden and involuntary muscle contractions that can sometimes be painful are known as spasms. If this occurs in the intestinal tract a bellyache can occur. If these come in multiples then seizures or convulsions can result. Long painful spasms are known as cramps. With a lot of effort a person can control facial tics. If a muscle is stretched or torn a strain can occur. If a joint is twisted a sprain can occur. If a tendon becomes injured or inflamed movement of a joint can be painful and tendonitis can result. Myalgia and fibromyalgia are two types of muscular diseases. Myalgia can result from overstretching or overworking muscles or can come from viral infections. The result is achy muscles. Fibromyalgia is chronic and causes achy pain, tenderness and stiffness of muscles. A progression of degenerating and weakening muscles is muscular dystrophy. Lou Gehrig’s disease has no cure and causes the inability to chew, talk, walk and swallow.
12.5- Homeostasis
Skeletal and muscular systems work together in maintain homeostasis, one assists the other with eating and moving, keeping the heart pumping, and breathing. While the skeletal system protects the soft organs the muscular system protects the abdominal organs. The skeletal system produces red bone marrow and regulates blood calcium while the muscular system helps regulate the body temperature, keeping it stable.
Unit 3- Ethical Issue Essay- Exercise
What Is It Going To Take?
In a world where obesity has become such an epidemic, what will it take for a change to take place? It is hard to see how anyone or group can be organizing exercise groups or physical activity pyramids and putting them to use. This sort of thing doesn't make the news or even the discovery channel, instead we see "World's Fattest Man" and "World's Fattest Man Gets Married." The way they have made this man some kind of celebrity is just sick to me!
I think it's great that Scotland promotes a more active lifestyle and that Island County has the physical activity pyramid, now if we could get people to go by this all over the world we might have a fighting chance. I believe that today people are so busy in their lives working and getting food on the table that come some down time, the thought of physical activity is exhausting let alone actually doing it. I work full time and I am taking three classes, so to squeeze exercise in there I thought I'd get up thirty minutes early every morning, I made it twice before giving up, so I get how finding the time can be hard. But at least eat right and put in a little physical activity throughout the day. You can do exercises while sitting at your desk.
So, if we could adopt the traits that it takes to stick to a physical activity pyramid or maybe bike to work or school and eat healthy we might be able to beat this epidemic, but as it sits right now I only see the problem getting worse. Maybe more people should use the MyPyramid Tracker, maybe that'll give them a wake up call.
In a world where obesity has become such an epidemic, what will it take for a change to take place? It is hard to see how anyone or group can be organizing exercise groups or physical activity pyramids and putting them to use. This sort of thing doesn't make the news or even the discovery channel, instead we see "World's Fattest Man" and "World's Fattest Man Gets Married." The way they have made this man some kind of celebrity is just sick to me!
I think it's great that Scotland promotes a more active lifestyle and that Island County has the physical activity pyramid, now if we could get people to go by this all over the world we might have a fighting chance. I believe that today people are so busy in their lives working and getting food on the table that come some down time, the thought of physical activity is exhausting let alone actually doing it. I work full time and I am taking three classes, so to squeeze exercise in there I thought I'd get up thirty minutes early every morning, I made it twice before giving up, so I get how finding the time can be hard. But at least eat right and put in a little physical activity throughout the day. You can do exercises while sitting at your desk.
So, if we could adopt the traits that it takes to stick to a physical activity pyramid or maybe bike to work or school and eat healthy we might be able to beat this epidemic, but as it sits right now I only see the problem getting worse. Maybe more people should use the MyPyramid Tracker, maybe that'll give them a wake up call.
Unit 3- Online Lab 2- Muscle Lab
Introduction: The purpose of this lab is to observe the muscles contracting before temperatures and fatigue and then to observe them once they are cold or fatigued to see the difference. Also this lab will help to recognize how the muscles are at resting and once contracted.
The supplies for this lab are:
bowl of water
ice or snow
timer or watch
paper
rubber ball or clothespin
This is a picture of my supplies:
This is a picture of my hand in the freeing cold water! You can't see it throbbing, but I felt it!!! :)
Temperature------ Number of Fists
Normal----------- 36
The supplies for this lab are:
bowl of water
ice or snow
timer or watch
paper
rubber ball or clothespin
This is a picture of my supplies:
This is a picture of my hand in the freeing cold water! You can't see it throbbing, but I felt it!!! :)
Temperature------ Number of Fists
Normal----------- 36
Ice Water--------- 22
Trial ----- # of Squeezes in 20 seconds
1------------ 40
2------------ 39
3------------ 36
4------------ 35
Trial ----- # of Squeezes in 20 seconds
1------------ 40
2------------ 39
3------------ 36
4------------ 35
5------------ 32
6------------ 29
7------------ 30
8------------ 27
6------------ 29
7------------ 30
8------------ 27
9------------ 26
10----------- 24
1. The three changes I noticed when my muscles were contracted were my muscle getting fatigued, it became shorter and stuck out a little bit more or bulged.
2. The cold water made my hand throb and caused my muscles to slow down, I was unable to clench my fist as many times as before putting my hand in the cold water.
3. The fatigue of my hand made it slower to clench my fist and to clench the ball.
10----------- 24
1. The three changes I noticed when my muscles were contracted were my muscle getting fatigued, it became shorter and stuck out a little bit more or bulged.
2. The cold water made my hand throb and caused my muscles to slow down, I was unable to clench my fist as many times as before putting my hand in the cold water.
3. The fatigue of my hand made it slower to clench my fist and to clench the ball.
Thursday, November 13, 2008
Unit 3- Online Lab 1- Leech Neurons
1. The electrode is measuring resting potential and action potential of the neuron.
2. The leech is used for this because they are large and easy enough to get access to. They attach themselves to the host without the host realizing it.
3. A motor neuron conducts nerve impulses away from the central nervous system, while a sensory neuron transmits nerve impulses to the central nervous system.
4. I think the leech experiences pain even if its only a tiny bit. The leech has sensory receptors like us making it sensitive to chemicals that are released when the tissue is damaged.
5. It was interesting cutting the leech up and being able to probe around on the tissue before turning the UV light on.
6. The only confusing part about the lab was computer being junky for a minute :) But once that was fixed I actually enjoyed doing this online lab.
Tuesday, November 11, 2008
Unit 3- Lab Project- Build a Limb
For this lab project I had to build a human limb, bones that meet at a joint, a muscle pulling on that bone, muscle cell showing how actin-myosin filaments make it contract and neurons that go to muscle cells triggering contraction. For the limb I chose a human leg. The supplies for my project included clay to show the muscle, skeleton bones left over from halloween, pipe cleaners for the neurons and actin-myosin, crazy eyes to show sodium ions and potassium ions, construction paper for labeling, pieces of a straw to show schwann cells and grape stems.
This is a picture of the supplies I used:
This is my human limb, the leg. The red clay on it is showing the muscle.
This is the leg laying down so that I could label the parts:
This is my version of an axon with the schwann cells. The little red pieces are the straw and the grape stem is the axon terminal and the dendrites.
Here I am showing the propagation of action potential along the axon:
This is the muscle cell, the sarcomeres are relaxed here, they are shorten:
And here the sarcomeres are contracted:
This picture is of the sodium ions (Na+) gates opening and starting to move inside the axon. Na+ goes before K+.
This is what happens next, the Na+ gates close allowing potassium ions (K+) to move out of the axon.
So in conclusion my models show the human limb and the muscle on it, the action potential and actin-myosin filaments that are required to get a limb to move and the axon with the schwann cells. This project has helped me to understand how our limbs move and what makes muscles contract. Without action potentials and actin-myosin filaments how would are limbs move?
This is a picture of the supplies I used:
This is my human limb, the leg. The red clay on it is showing the muscle.
This is the leg laying down so that I could label the parts:
This is my version of an axon with the schwann cells. The little red pieces are the straw and the grape stem is the axon terminal and the dendrites.
Here I am showing the propagation of action potential along the axon:
This is the muscle cell, the sarcomeres are relaxed here, they are shorten:
And here the sarcomeres are contracted:
This picture is of the sodium ions (Na+) gates opening and starting to move inside the axon. Na+ goes before K+.
This is what happens next, the Na+ gates close allowing potassium ions (K+) to move out of the axon.
So in conclusion my models show the human limb and the muscle on it, the action potential and actin-myosin filaments that are required to get a limb to move and the axon with the schwann cells. This project has helped me to understand how our limbs move and what makes muscles contract. Without action potentials and actin-myosin filaments how would are limbs move?Compendium Review Unit 3/ Topic 1: Enviromental Interactions
Compendium Review Unit 3- The Body- Topic 1- Environmental Interactions
Chapter 13- Nervous System
13.1- Overview of the Nervous System
13.2- The Central Nervous System
13.3- The Limbic System and Higher Mental Functions
13.4- The Peripheral Nervous System
13.5- Drug Abuse
13.1 Overview of the Nervous System
The nervous system has 2 major divisions that are connected and work together they are the central nervous system (CNS) and the peripheral nervous system (PNS). PNS consists of nerves while CNS consists of the brain and spinal cord. The three specific functions of the nervous system are 1- the nervous system gets sensory input, 2- CNS adds up all the input it gets from the body and 3- generates motor output, nerve impulses go from CNS by way of the PNS to the muscles and glands.
Neurons are cells that transmit nerve impulses and neuroglia are what support and nourish neurons. Both are cells that make up nervous tissue. Sensory neurons, interneurons an motor neurons are the three types of neurons. The sensory neuron takes messages from a sensory receptor to the CNS. Special structures that detect changes in the environment are sensory receptors. Interneurons lie entirely within the CNS. They get input from both sensory neurons and other interneurons. They add up all the received info before communicating with motor neurons. Motor neurons take nerve impulses from the CNS to an effector or muscle fiber or gland. Effectors are what carry out responses to environment changes. Neurons are made up of three parts- cell boy, dendrites and an axon. Nucleus and other organelles make up the cell body. Short extensions that get signals from sensory receptors and neurons make up dendrites. The portion of the neuron which conducts nerve impulses is known as the axon.
Types of neurons are shown below:
Myelin sheath is what protects axons. For the PNS it is made b neuroglia known as schwann cells- contact myelin in plasma membranes. Oligodendrocytes in the CNS do this. When cells wrap around axons the myelin sheath is made. Nodes of ranvier are the gaps where no myelin sheath is. Short axons do not have myelin sheath. White matter in CNS has myelinated axons, gray area does not. Loss of myelin sheath can result in MS or leukodystrophies.
Resting potential occurs when the axon is not conducting an impulse. -65 mV inside the neuron is more negative than outside.
Sodium-potassium pump transports sodium ions (Na+) out of potassium ions (K+) into the axon. This is what maintains unequal distribution of both across the membrane. Always more positive ions outside the membrane. Rapid change in polarity is action potential- this happens if the axonal membrane depolarizes to threshold. Gates will open letting K+ and Na+ pass through the membrane. Sodium gates open first- Na+ goes to the axon causing potential changes -65mV to +40mV which is depolarization- the inside of the neuron goes negative to positive. Potassium gates open next and K+ goes to the axon and repolarization occurs +40 mV back to -65mV. Nerve impulses going from nerve to nerve is called salutatory conduction. The refractory period keeps the sodium gates closed keeping action potential from going backwards.
Axon terminals are small swellings at the end of axon branches. The synapse is the region of the close proximity, small gaps that separate sending neurons from receiving neurons are the synaptic cleft. Neurotransmitters are what helps get nerve impulses over the cleft. Once neurotransmitters initiate responses they leave the cleft. Acetylcholinesterase is an enzyme that inactivates neurotransmitters.
Synapse structure & function shown below:
Serotonin is a neurotransmitter that is involved with sleeping, emotions and perception, norepinephrine is too but it is involved with waking, dreaming and mood. Lower levels of these are linked with depression. Neuromodulators are molecules that block the release of neurotransmitters. Substance P is released when in pain, endorphins block the release of this. Both are neuromodulators.
13.2- The Central Nervous System
The spinal cord and the brain which make up the CNS are protected by bone; the vertebrae protects the spine the skull protects the brain. Protective membranes that wrap and protect both of these are known as meninges. Cerebrospinal fluid fills the spaces between the meninges and it cushions and protects the central nervous system. Interconnecting chambers that produce and serve as a reservoir for the fluid are known as ventricles. The brain has four of these. Water on the brain is a condition called hydrocephalus. Gray matter is one type of nervous tissue that contains cell bodies and short nonmyelineated fibers. The other type is known as white matter which contains mylineated axons that run together in bundled called tracts.
The meninges and central canal contain cerebrospinal fluid that protects the spinal cord. Spinal nerves are part of the peripheral nervous system. The right side of the brain controls the left side of the body, left side of the brain controls the right side of the body. Communication between the brain and peripheral nerves leaving the cord is provided with the spinal cord. Endorphins can stop pain otherwise the pain messages will pass through the gates to the brain. Paralysis occurs if the spinal cord is severed, meaning no voluntary muscle control. If the cord is severed in the thoracic area then the lower body is affected- the legs are paralyzed, which makes the person a paraplegic. Quadriplegic is when the injury happens in the neck area making all four limps paralyzed. Thousands of reflexes happen in the spinal cord.
The largest part of the brain is the cerebrum, which is the last part to receive sensory input and carry out integration before commanding voluntary motor responses. The cerebrum consists of two halves, the right cerebral hemisphere and the left hemisphere. It is split in half by a deep groove known as the longitudinal fissure. The hemispheres are divided into lobes by shallow grooves known as sulci.
The lobes of the hemisphere are shown below:
The cerebral cortex is known as an outer layer of gray matter that covers the cerebral hemispheres. Over one billion cell bodies are in the cortex. This part of the brain is associated with sensation, voluntary movement and the thought processes. Motor and sensory areas are in the cerebral cortex. The frontal lobe has the primary motor area. Sensory info from the skin and skeletal muscle goes to the primary somatosensory area. Integration occurs in association areas. The premotor area organizes motor functions like walking and talking at the same time. The processing centers of the cortex receive info from association areas and perform higher level functions. Prefrontal area gets info and plans our actions, the ability to think critically and formulate appropriate behaviors is because of integration in this area. Wernicke’s area and Broca’s area are partly responsible for humans speaking, both areas are found in the left cerebral cortex. Wernicke’s helps us to understand written and spoken words sending the info to Broca’s. White matter makes up most of the rest of the cerebrum. A region that encircles the third ventricle is known as the diencephalon. This is where the hypothalamus and thalamus are located. The hypothalamus helps in maintaining homeostasis and also is a link between the nervous system and the endocrine system. The thalamus receives all sensory input except smell. The thalamus integrates the info and sends it to the right part of the cerebrum. Also the thalamus helps in higher mental functions like memory and emotions. The fourth ventricle is what separates the cerebellum from the brain stem. Sensory input from the eyes, ears, joints and muscles is received from the cerebellum once this information is integrated the cerebellum sends motor impulses to the skeletal muscles. The relay station for the tracts passing between the cerebrum and spinal cord is the midbrain. Pons contains bundles of axons traveling between the cerebellum and the central nervous system. Reflex centers that regulate heart beat and breathing are in the medulla oblongata. The reticular formation is the network of nuclei and fibers that extend the length of the brain stem. The reticular activating system gets sensory signals and sends them up to higher centers.
13.3- The Limbic System and Higher Mental Functions
The limbic system is responsible for why sexual behavior and eating seem pleasurable and why mental stress can cause high blood pressure. The amygdala which can cause experiences to have emotional overtones is part of the limbic system. Also the hippocampus is another part to the limbic system, which is crucial to learning and memory. The prefrontal area of our brains is responsible for short term memory, once something is memorized it is put into long term memory. Semantic memory is a mixture, like numbers, words, etc. Episodic memory is related to people or events. Skill memory is used in performing motor activities. Memories are stored in the hippocampus and are utilized in the prefrontal area. Language depends on semantic memory.
13.4- The Peripheral Nervous System
Nerves are designated as cranial nerves when they arise from the brain and spinal nerves when they arise from the spinal cord. Nerves are made up of axons. Twelve pairs of cranial nerves attached to the brain, some have only motor fibers, some only sensory fibers and others have both. The cell body of a sensory neuron is in a dorsal root ganglion. A collection of cell bodies outside the CNS is known as a ganglion. Spinal nerves consist of sensory and motor fibers and therefore are mixed nerves. The somatic system nerves serve the skin, skeletal muscles and tendons. Reflexes occur when automatic responses to a stimulus in the somatic system. Pain is not felt until the brain receives and interprets the information.
Chapter 13- Nervous System
13.1- Overview of the Nervous System
13.2- The Central Nervous System
13.3- The Limbic System and Higher Mental Functions
13.4- The Peripheral Nervous System
13.5- Drug Abuse
13.1 Overview of the Nervous System
The nervous system has 2 major divisions that are connected and work together they are the central nervous system (CNS) and the peripheral nervous system (PNS). PNS consists of nerves while CNS consists of the brain and spinal cord. The three specific functions of the nervous system are 1- the nervous system gets sensory input, 2- CNS adds up all the input it gets from the body and 3- generates motor output, nerve impulses go from CNS by way of the PNS to the muscles and glands.
Neurons are cells that transmit nerve impulses and neuroglia are what support and nourish neurons. Both are cells that make up nervous tissue. Sensory neurons, interneurons an motor neurons are the three types of neurons. The sensory neuron takes messages from a sensory receptor to the CNS. Special structures that detect changes in the environment are sensory receptors. Interneurons lie entirely within the CNS. They get input from both sensory neurons and other interneurons. They add up all the received info before communicating with motor neurons. Motor neurons take nerve impulses from the CNS to an effector or muscle fiber or gland. Effectors are what carry out responses to environment changes. Neurons are made up of three parts- cell boy, dendrites and an axon. Nucleus and other organelles make up the cell body. Short extensions that get signals from sensory receptors and neurons make up dendrites. The portion of the neuron which conducts nerve impulses is known as the axon.
Types of neurons are shown below:
Myelin sheath is what protects axons. For the PNS it is made b neuroglia known as schwann cells- contact myelin in plasma membranes. Oligodendrocytes in the CNS do this. When cells wrap around axons the myelin sheath is made. Nodes of ranvier are the gaps where no myelin sheath is. Short axons do not have myelin sheath. White matter in CNS has myelinated axons, gray area does not. Loss of myelin sheath can result in MS or leukodystrophies.Resting potential occurs when the axon is not conducting an impulse. -65 mV inside the neuron is more negative than outside.
Sodium-potassium pump transports sodium ions (Na+) out of potassium ions (K+) into the axon. This is what maintains unequal distribution of both across the membrane. Always more positive ions outside the membrane. Rapid change in polarity is action potential- this happens if the axonal membrane depolarizes to threshold. Gates will open letting K+ and Na+ pass through the membrane. Sodium gates open first- Na+ goes to the axon causing potential changes -65mV to +40mV which is depolarization- the inside of the neuron goes negative to positive. Potassium gates open next and K+ goes to the axon and repolarization occurs +40 mV back to -65mV. Nerve impulses going from nerve to nerve is called salutatory conduction. The refractory period keeps the sodium gates closed keeping action potential from going backwards.
Axon terminals are small swellings at the end of axon branches. The synapse is the region of the close proximity, small gaps that separate sending neurons from receiving neurons are the synaptic cleft. Neurotransmitters are what helps get nerve impulses over the cleft. Once neurotransmitters initiate responses they leave the cleft. Acetylcholinesterase is an enzyme that inactivates neurotransmitters.
Synapse structure & function shown below:
Serotonin is a neurotransmitter that is involved with sleeping, emotions and perception, norepinephrine is too but it is involved with waking, dreaming and mood. Lower levels of these are linked with depression. Neuromodulators are molecules that block the release of neurotransmitters. Substance P is released when in pain, endorphins block the release of this. Both are neuromodulators.
13.2- The Central Nervous System
The spinal cord and the brain which make up the CNS are protected by bone; the vertebrae protects the spine the skull protects the brain. Protective membranes that wrap and protect both of these are known as meninges. Cerebrospinal fluid fills the spaces between the meninges and it cushions and protects the central nervous system. Interconnecting chambers that produce and serve as a reservoir for the fluid are known as ventricles. The brain has four of these. Water on the brain is a condition called hydrocephalus. Gray matter is one type of nervous tissue that contains cell bodies and short nonmyelineated fibers. The other type is known as white matter which contains mylineated axons that run together in bundled called tracts.
The meninges and central canal contain cerebrospinal fluid that protects the spinal cord. Spinal nerves are part of the peripheral nervous system. The right side of the brain controls the left side of the body, left side of the brain controls the right side of the body. Communication between the brain and peripheral nerves leaving the cord is provided with the spinal cord. Endorphins can stop pain otherwise the pain messages will pass through the gates to the brain. Paralysis occurs if the spinal cord is severed, meaning no voluntary muscle control. If the cord is severed in the thoracic area then the lower body is affected- the legs are paralyzed, which makes the person a paraplegic. Quadriplegic is when the injury happens in the neck area making all four limps paralyzed. Thousands of reflexes happen in the spinal cord.
The largest part of the brain is the cerebrum, which is the last part to receive sensory input and carry out integration before commanding voluntary motor responses. The cerebrum consists of two halves, the right cerebral hemisphere and the left hemisphere. It is split in half by a deep groove known as the longitudinal fissure. The hemispheres are divided into lobes by shallow grooves known as sulci.
The lobes of the hemisphere are shown below:
The cerebral cortex is known as an outer layer of gray matter that covers the cerebral hemispheres. Over one billion cell bodies are in the cortex. This part of the brain is associated with sensation, voluntary movement and the thought processes. Motor and sensory areas are in the cerebral cortex. The frontal lobe has the primary motor area. Sensory info from the skin and skeletal muscle goes to the primary somatosensory area. Integration occurs in association areas. The premotor area organizes motor functions like walking and talking at the same time. The processing centers of the cortex receive info from association areas and perform higher level functions. Prefrontal area gets info and plans our actions, the ability to think critically and formulate appropriate behaviors is because of integration in this area. Wernicke’s area and Broca’s area are partly responsible for humans speaking, both areas are found in the left cerebral cortex. Wernicke’s helps us to understand written and spoken words sending the info to Broca’s. White matter makes up most of the rest of the cerebrum. A region that encircles the third ventricle is known as the diencephalon. This is where the hypothalamus and thalamus are located. The hypothalamus helps in maintaining homeostasis and also is a link between the nervous system and the endocrine system. The thalamus receives all sensory input except smell. The thalamus integrates the info and sends it to the right part of the cerebrum. Also the thalamus helps in higher mental functions like memory and emotions. The fourth ventricle is what separates the cerebellum from the brain stem. Sensory input from the eyes, ears, joints and muscles is received from the cerebellum once this information is integrated the cerebellum sends motor impulses to the skeletal muscles. The relay station for the tracts passing between the cerebrum and spinal cord is the midbrain. Pons contains bundles of axons traveling between the cerebellum and the central nervous system. Reflex centers that regulate heart beat and breathing are in the medulla oblongata. The reticular formation is the network of nuclei and fibers that extend the length of the brain stem. The reticular activating system gets sensory signals and sends them up to higher centers.13.3- The Limbic System and Higher Mental Functions
The limbic system is responsible for why sexual behavior and eating seem pleasurable and why mental stress can cause high blood pressure. The amygdala which can cause experiences to have emotional overtones is part of the limbic system. Also the hippocampus is another part to the limbic system, which is crucial to learning and memory. The prefrontal area of our brains is responsible for short term memory, once something is memorized it is put into long term memory. Semantic memory is a mixture, like numbers, words, etc. Episodic memory is related to people or events. Skill memory is used in performing motor activities. Memories are stored in the hippocampus and are utilized in the prefrontal area. Language depends on semantic memory.
13.4- The Peripheral Nervous System
Nerves are designated as cranial nerves when they arise from the brain and spinal nerves when they arise from the spinal cord. Nerves are made up of axons. Twelve pairs of cranial nerves attached to the brain, some have only motor fibers, some only sensory fibers and others have both. The cell body of a sensory neuron is in a dorsal root ganglion. A collection of cell bodies outside the CNS is known as a ganglion. Spinal nerves consist of sensory and motor fibers and therefore are mixed nerves. The somatic system nerves serve the skin, skeletal muscles and tendons. Reflexes occur when automatic responses to a stimulus in the somatic system. Pain is not felt until the brain receives and interprets the information.
A reflex arc is shown below:
The autonomic system is what regulates the activity of cardiac and smooth muscles and glands. This system is in the PNS. Sympathetic and parasympathetic divisions make up the autonomic system. Both function automatically and involuntary, they innervate all internal organs, and they utilize two neurons and one ganglion for each impulse. Preganglionic fibers of the sympathetic division come from the middle of the spinal cord and terminate in ganglia that lie near the cord. This division is important in emergency situations. The parasympathetic division consists of cranial nerves and fibers that come from the bottom part of the spinal cord. All the internal responses we associate with a relaxed state is in this division, also known as the housekeeper division. Both the somatic system and autonomic system are in the peripheral nervous system.
13.5- Drug Abuse
Drugs which consist of natural molecules or synthetically derived affect the nervous system, they alter the mood and our emotional state. They increase or decrease the action of a particular neurotransmitter and affect the limbic system. Dopamine has a role in mood. Psychological dependence on a drug is obvious when a person craves a drug, spends time looking for the drug and uses it regularly. The person is shows physical dependence or is addicted when they need more and more to reach the same high and they show withdrawal symptoms when they stop taking the drug. The most socially excepted form of drug use is alcoholism. A long time use of alcohol can harm the liver and make it function less. If alcohol blood level gets to high coma or death can result. Alcohol acts as a depressant in the CNS. Brain size can decrease with chronic use of alcohol. Nicotine is a stimulant, when it reaches the CNS it binds to the neurons and dopamine is released. In the PNS skeletal muscle activity increases. Cocaine use leads to a rush of well being that can last five to thirty minutes. The use of this drug brings on lack of appetite, sleeplessness and an increased sex drive. Crack is the street name for cocaine and is the form of smoking it. Dopamine is made less to make up for the excess of synapses with continued use. Methamphetamine is known as speed, which is powder form or crystal meth or ice which is in crystal form. Heroin acts as a depressant in the nervous system. Heroin is delivered to the brain and converted to morphine. Heroin can be smoked, injected or snorted. When marijuana reaches the CNS mild euphoria can occur. Regular use of marijuana can lead o cravings. This can have an effect on memory, balance, motor coordination and orientation.
Chapter 14: Senses
14.1- Sensory Receptors and Sensations
14.2- Proprioceptors and Cutaneous Receptors
14.3- Senses of Taste and Smell
14.4- Sense of Vision
14.5- Sense of Hearing
14.6- Sense of Equilibrium
14.1- Sensory Receptors and Sensations
The dendrites specialized to detect certain types of stimuli are known as sensory receptors. Sensory receptors that detect stimuli from outside the body are known as exterocceptors. Interoceptors get stimuli from inside the body and are involved in homeostasis. Four types of sensory receptors are chemoreceptors, photoreceptors, mechanoreceptors, and thermoreceptors. A response to chemical substances is chemoreceptors. Pain receptors are a type of chemoreceptors, they alert us to possible danger. Response to light energy is photoreceptors which are in our eyes. Mechanical forces stimulate our mechanoreceptors (located in our ear) usually with some kind of pressure. They also help to keep our balance. Thermoreceptors are located in the hypothalamus and the skin and respond in temperature changes. Warmth receptors respond when temperatures rise and cold receptors respond in lower temperatures.
Sensations occur when nerve impulses get to the cerebral cortex. All sensory receptors initiate nerve impulses but the sensation depends on what part of the brain receives the impulse. Integration is carried out before the sensory receptors initiate the nerve impulse. A decrease in response to a stimulus is known as sensory adaptation. Sensory receptors functioning helps maintain homeostasis.
14.2- Proprioceptors and Cutaneous Receptors
Three types of general sensory receptors are known as proprioceptors, cutaneous receptors and pain receptors. Maintaining muscle tone and the body’s equilibrium and posture is due to proprioceptors which are mechanoreceptors involved in reflex. Nerve impulses occur when the muscle relaxes and undue stretching of the muscle spindle occurs. The dermis, which is a layer of the skin, contains cutaneous receptors. This makes the skin sensitive to touch, pain, pressure and temperature. Pain receptors are in the skin and many internal organs. Referred pain is when stimulation of internal pain receptors is felt as pain from the skin as well as internal organs.
14.3- Senses of Taste and Smell
Chemical senses are taste and smell. Chemoreceptors are present in taste cells. Four primary types of taste are sweet, salty, sour and bitter. Taste cells end in microvilli, this helps distinguish the taste. Adults have about 3,000 taste buds. 80-90% of what we taste is due to smell. High in the roof of the nasal cavity is where 10 and 20 million olfactory cells are located, our sense of smell depends on these cells. Olfactory cells are connected with the limbic system, certain smells can take us back to a person or place.
14.4- Sense of Vision
There are three layers to the eyeball which is 2.5 cm in diameter. The layers are the sclera which is the outer layer made of white and fibrous except the cornea, the choroid which is the middle layer that absorbs light rays that have not yet been absorbed by photoreceptors and the retina which is what helps us to see black and white, color and acute vision. The iris is what the choroid becomes toward the front of the eyeball and is what regulates the pupil. The pupil is what allows light in. The shape of the lens for near and far vision is controlled by the ciliary body. The posterior compartment of the eye (behind the lens) is separated from the anterior compartment (in front of the lens) by the lens. Aqueous humor is a clear watery fluid that fills the anterior compartment, this fluid is made daily. Tiny ducts are how this fluid is released, if they become blocked then glaucoma can occur, this can lead to blindness. A clear gelatin material known as vitreous humor is located in the posterior compartment. The fovea centralis is located in the retina and is where cone cells are packed. The optic nerve is what takes nerve impulses to the visual cortex. The lens, humors and cornea help focus things on the retina. Visual accommodation involves the lens rounding up bringing the image to focus on the retina during close vision. Rod cells and cone cells are photoreceptors. Rhodopsin is a molecule made of protein opsin and retinal, a light absorbing molecule. Rods help with peripheral vision and perception of motion. Carrots, being high in vitamin A help our night vision. The three kinds of cones that help us with color vision are the B (blue), G (green) and R (red) pigments. The retina is made up of three layers of neurons. Layer closest to the choroid has rod cells and cone cells, middle layer is bipolar cells and the inner layer has ganglion cells.
Structure & function of the retina is shown below:
A blind spot occurs for the left eye left of center and for the right eye right of center. Blind spots occur because there are no rods or cones where the optic nerve exits making no vision possible. The blind spot only happens for one eye, not when using both eyes. Optic nerves carry nerve impulses from the eyes to the optic chiasma, which is X shapped, crossing over optic nerves.
Some abnormalities of the eye include color blindness and misshapen eyeballs, 5-8% of males are affected with color blindness. Also nearsighted which means you can see better close up than at a distance, and farsighted which means you can see better at a distance than close up. When light rays cannot be evenly focused on the retina it is known as astigmatism.
14.5- Sense of Hearing
Hearing and balance are the two sensory functions of the ear. Hair cells located in the inner ear are the sensory receptors, mechanoreceptors. Three divisions of the ear include the outer ear, pinna the external flap and auditory canal, the middle ear at the tympanic membrane or the eardrum and the inner ear which unlike the first two divisions contains fluid instead of air.
Anatomy of the human ear is shown below:
The semicircular canals and vestibule of the inner ear work for equilibrium and the cochlea works for hearing. The outer ear gets the sound, middle ear magnifies the sound and strikes the oval window causing a vibration making pressure pass to the fluid in the cochlea.
14.6- Sense of Equilibrium
Nerve impulses are taken to the brain stem and the cerebellum by way of the vestibular nerve. The vestibular nerve helps maintain equilibrium. Rotational equilibrium is detected by the mechanoreceptors in the semicircular canals when movement of the head occurs. Gravitational equilibrium is when the mechanoreceptors in the utricle and saccule detect movement of the head.
Mechanoreceptors for equilibrium are shown below:
The autonomic system is what regulates the activity of cardiac and smooth muscles and glands. This system is in the PNS. Sympathetic and parasympathetic divisions make up the autonomic system. Both function automatically and involuntary, they innervate all internal organs, and they utilize two neurons and one ganglion for each impulse. Preganglionic fibers of the sympathetic division come from the middle of the spinal cord and terminate in ganglia that lie near the cord. This division is important in emergency situations. The parasympathetic division consists of cranial nerves and fibers that come from the bottom part of the spinal cord. All the internal responses we associate with a relaxed state is in this division, also known as the housekeeper division. Both the somatic system and autonomic system are in the peripheral nervous system.
13.5- Drug Abuse
Drugs which consist of natural molecules or synthetically derived affect the nervous system, they alter the mood and our emotional state. They increase or decrease the action of a particular neurotransmitter and affect the limbic system. Dopamine has a role in mood. Psychological dependence on a drug is obvious when a person craves a drug, spends time looking for the drug and uses it regularly. The person is shows physical dependence or is addicted when they need more and more to reach the same high and they show withdrawal symptoms when they stop taking the drug. The most socially excepted form of drug use is alcoholism. A long time use of alcohol can harm the liver and make it function less. If alcohol blood level gets to high coma or death can result. Alcohol acts as a depressant in the CNS. Brain size can decrease with chronic use of alcohol. Nicotine is a stimulant, when it reaches the CNS it binds to the neurons and dopamine is released. In the PNS skeletal muscle activity increases. Cocaine use leads to a rush of well being that can last five to thirty minutes. The use of this drug brings on lack of appetite, sleeplessness and an increased sex drive. Crack is the street name for cocaine and is the form of smoking it. Dopamine is made less to make up for the excess of synapses with continued use. Methamphetamine is known as speed, which is powder form or crystal meth or ice which is in crystal form. Heroin acts as a depressant in the nervous system. Heroin is delivered to the brain and converted to morphine. Heroin can be smoked, injected or snorted. When marijuana reaches the CNS mild euphoria can occur. Regular use of marijuana can lead o cravings. This can have an effect on memory, balance, motor coordination and orientation.
Chapter 14: Senses
14.1- Sensory Receptors and Sensations
14.2- Proprioceptors and Cutaneous Receptors
14.3- Senses of Taste and Smell
14.4- Sense of Vision
14.5- Sense of Hearing
14.6- Sense of Equilibrium
14.1- Sensory Receptors and Sensations
The dendrites specialized to detect certain types of stimuli are known as sensory receptors. Sensory receptors that detect stimuli from outside the body are known as exterocceptors. Interoceptors get stimuli from inside the body and are involved in homeostasis. Four types of sensory receptors are chemoreceptors, photoreceptors, mechanoreceptors, and thermoreceptors. A response to chemical substances is chemoreceptors. Pain receptors are a type of chemoreceptors, they alert us to possible danger. Response to light energy is photoreceptors which are in our eyes. Mechanical forces stimulate our mechanoreceptors (located in our ear) usually with some kind of pressure. They also help to keep our balance. Thermoreceptors are located in the hypothalamus and the skin and respond in temperature changes. Warmth receptors respond when temperatures rise and cold receptors respond in lower temperatures.
Sensations occur when nerve impulses get to the cerebral cortex. All sensory receptors initiate nerve impulses but the sensation depends on what part of the brain receives the impulse. Integration is carried out before the sensory receptors initiate the nerve impulse. A decrease in response to a stimulus is known as sensory adaptation. Sensory receptors functioning helps maintain homeostasis.
14.2- Proprioceptors and Cutaneous Receptors
Three types of general sensory receptors are known as proprioceptors, cutaneous receptors and pain receptors. Maintaining muscle tone and the body’s equilibrium and posture is due to proprioceptors which are mechanoreceptors involved in reflex. Nerve impulses occur when the muscle relaxes and undue stretching of the muscle spindle occurs. The dermis, which is a layer of the skin, contains cutaneous receptors. This makes the skin sensitive to touch, pain, pressure and temperature. Pain receptors are in the skin and many internal organs. Referred pain is when stimulation of internal pain receptors is felt as pain from the skin as well as internal organs.
14.3- Senses of Taste and Smell
Chemical senses are taste and smell. Chemoreceptors are present in taste cells. Four primary types of taste are sweet, salty, sour and bitter. Taste cells end in microvilli, this helps distinguish the taste. Adults have about 3,000 taste buds. 80-90% of what we taste is due to smell. High in the roof of the nasal cavity is where 10 and 20 million olfactory cells are located, our sense of smell depends on these cells. Olfactory cells are connected with the limbic system, certain smells can take us back to a person or place.
14.4- Sense of Vision
There are three layers to the eyeball which is 2.5 cm in diameter. The layers are the sclera which is the outer layer made of white and fibrous except the cornea, the choroid which is the middle layer that absorbs light rays that have not yet been absorbed by photoreceptors and the retina which is what helps us to see black and white, color and acute vision. The iris is what the choroid becomes toward the front of the eyeball and is what regulates the pupil. The pupil is what allows light in. The shape of the lens for near and far vision is controlled by the ciliary body. The posterior compartment of the eye (behind the lens) is separated from the anterior compartment (in front of the lens) by the lens. Aqueous humor is a clear watery fluid that fills the anterior compartment, this fluid is made daily. Tiny ducts are how this fluid is released, if they become blocked then glaucoma can occur, this can lead to blindness. A clear gelatin material known as vitreous humor is located in the posterior compartment. The fovea centralis is located in the retina and is where cone cells are packed. The optic nerve is what takes nerve impulses to the visual cortex. The lens, humors and cornea help focus things on the retina. Visual accommodation involves the lens rounding up bringing the image to focus on the retina during close vision. Rod cells and cone cells are photoreceptors. Rhodopsin is a molecule made of protein opsin and retinal, a light absorbing molecule. Rods help with peripheral vision and perception of motion. Carrots, being high in vitamin A help our night vision. The three kinds of cones that help us with color vision are the B (blue), G (green) and R (red) pigments. The retina is made up of three layers of neurons. Layer closest to the choroid has rod cells and cone cells, middle layer is bipolar cells and the inner layer has ganglion cells.
Structure & function of the retina is shown below:
A blind spot occurs for the left eye left of center and for the right eye right of center. Blind spots occur because there are no rods or cones where the optic nerve exits making no vision possible. The blind spot only happens for one eye, not when using both eyes. Optic nerves carry nerve impulses from the eyes to the optic chiasma, which is X shapped, crossing over optic nerves.Some abnormalities of the eye include color blindness and misshapen eyeballs, 5-8% of males are affected with color blindness. Also nearsighted which means you can see better close up than at a distance, and farsighted which means you can see better at a distance than close up. When light rays cannot be evenly focused on the retina it is known as astigmatism.
14.5- Sense of Hearing
Hearing and balance are the two sensory functions of the ear. Hair cells located in the inner ear are the sensory receptors, mechanoreceptors. Three divisions of the ear include the outer ear, pinna the external flap and auditory canal, the middle ear at the tympanic membrane or the eardrum and the inner ear which unlike the first two divisions contains fluid instead of air.
Anatomy of the human ear is shown below:
The semicircular canals and vestibule of the inner ear work for equilibrium and the cochlea works for hearing. The outer ear gets the sound, middle ear magnifies the sound and strikes the oval window causing a vibration making pressure pass to the fluid in the cochlea.14.6- Sense of Equilibrium
Nerve impulses are taken to the brain stem and the cerebellum by way of the vestibular nerve. The vestibular nerve helps maintain equilibrium. Rotational equilibrium is detected by the mechanoreceptors in the semicircular canals when movement of the head occurs. Gravitational equilibrium is when the mechanoreceptors in the utricle and saccule detect movement of the head.
Mechanoreceptors for equilibrium are shown below:
Work Cited:
Mader, Sylvia S. Human Biology 1oth ed. McGraw Hill Companies, 2008.
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