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35 Cards in this Set
- Front
- Back
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Define homeostasis
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Homeostasis is maintaining the internal environment of the body at constant levels or between narrow limits.
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What in the body is maintained between narrow limits?
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temperature
blood pH oxygen concentrations carbon dioxide concentrations blood glucose concentration water/solute balance |
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THe internal environment varies very little. True/False
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True. The internal environment is controlled and varies very little, despite large variations in the external environment.
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What two systems play a major role in maintaining homeostasis?
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The Nervous and Endocrine Systems
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is homeostasis maintained by negative or positive feedback?
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Negative Feedback
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How does negative feedback work?
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A rise in levels feeds back to decrease production and reduce the level.
A decrease in levels feeds back to increase production and raise the level. |
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Do small fluctuations cause a response to be triggered? (Ex. Do small fluctuations in body temperature cause responses to be triggered?)
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No. Small fluctuations above and below the set point DO NOT cause a response.
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When does negative feedback come into play then?
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When the level rises significantly above the set point, it is then reduced by negative feedback.
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What are the two parts of the nervous system?
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Central nervous system &
Peripheral nervous system |
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What does the Central Nervous System consist of?
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Brain & Spinal Cord
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Define homeostasis
|
Homeostasis is maintaining the internal environment of the body at constant levels or between narrow limits.
|
|
|
What in the body is maintained between narrow limits?
|
temperature
blood pH oxygen concentrations carbon dioxide concentrations blood glucose concentration water/solute balance |
|
|
THe internal environment varies very little. True/False
|
True. The internal environment is controlled and varies very little, despite large variations in the external environment.
|
|
|
What two systems play a major role in maintaining homeostasis?
|
The Nervous and Endocrine Systems
|
|
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is homeostasis maintained by negative or positive feedback?
|
Negative Feedback
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|
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How does negative feedback work?
|
A rise in levels feeds back to decrease production and reduce the level.
A decrease in levels feeds back to increase production and raise the level. |
|
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Do small fluctuations cause a response to be triggered? (Ex. Do small fluctuations in body temperature cause responses to be triggered?)
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No. Small fluctuations above and below the set point DO NOT cause a response.
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When does negative feedback come into play then?
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When the level rises significantly above the set point, it is then reduced by negative feedback.
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What are the two parts of the nervous system?
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Central nervous system &
Peripheral nervous system |
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What does the Central Nervous System consist of?
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Brain & Spinal Cord
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What does the peripheral nervous system consist of?
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Peripheral nerves that connect all parts of the body to the central nervous system
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When you feel cold, do skin arerioles become narrower or wider? As a result, is more blood or less blood brought?
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Skine arterioles become narrower and they bring less blood.
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What happens inside the body when you shiver?
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Skeletal muscles do many small rapid contractions in order to generate heat.
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When you're cold, the temperature of your skin falls. So is less heat or more heat lost from your skin to the environment?
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Less heat. The temperature of your skin falls, so there is very little heat, therefore less heat is lost to the environment.
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When you are feeling hot, do your skin arterioles become wider or narrower?
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Wider, so more blood flows through the skin.
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Is more heat or less heat lost to the environment when you're feeling hot?
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More heat. The blood transfers heat from the core of your body to the skin. As a result the temperature of the skin rises, thus more heat is lost to the environment.
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What do sweat glands do when your body is overheated?
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Sweat glands secrete large amounts of sweat making the surface of the skin damp. Water evaporates from the damp skin and this has a cooling effect.
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What happens when you have a high blood glucose level (in terms of insulin)?
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Insulin stimulates the liver and muscle cells to absorb glucose from the blood and convert it to glycogen.
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What happens to the glycogen after its been converted?
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Granules of glycogen are stored in the cytoplasm. Other cells are stimulated to absorb glucose and use it in cell respiration istead of fat.
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When the blood glucose levels are low, what do the alpha cells produce? Where are the alpha cells?
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They produce glucagon.
Alpha cells are in the pancreatic islets |
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What does glucagon do when the blood glucose level is low?
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Glucagon stimulates liver cells to break glycogen down into glucose and release the glucose into the blood.
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What does the endocrine system consist of?
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It consists of glands which release hormones that are transported in the blood.
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Define excretion
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Excretion is the removal from the body of the toxic waste products of metabolism.
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What is the kidney's role in excretion?
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Waste products of metabolism are carried from the body cells to the kidney by the blood system. Kidneys remove waste products from the blood and produce urine containing them.
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What role do the kidneys play in homeostasis?
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Kidneys help to keep the water and salt content of the blood and tissue fluid constant. Kidneys have a role in homeostasis by varying the composition and volume of urine.
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