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26 Cards in this Set
- Front
- Back
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Glucagon
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The Alpha Cells in the Pancreas produce Glucagon
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Insulin
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The Beta Cells in the Pancreas produce Insulin
-is a protein hormone |
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Hormones that control blood glucose?
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#Insulin
#Glucagon both are made in the pancreas |
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Action of Glucagon
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...When blood glucose drops:
-promotes the breakdown of GLYCOGEN into glucose -Glucose is then released into the blood -INCREASES the level of blood glucose |
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Action of Insulin
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...When blood glucose increases:
-promotes uptake of glucose into the cells -glucose is stored as GLYCOGEN in order for more glucose to be taken -DECREASES blood glucose |
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After a meal=Hyperglycaemia 1
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-Insulin is secreted by the BETA cells because B.G levels are too high
-travels via the bloodstream to reach the target organs Liver and Muscles |
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After a meal=Hyperglycaemia 2.
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-Insulin binds to PROTEIN KINASE receptors in the cell membrane.
-It increases the uptake of glucose from the blood -converts glucose to glycogen and fat within the cell -reduces conversion of glycogen into glucose |
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After a meal=Hyperglycaemia 3
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-All these responses lower the overall concentration of glucose in the blood back to it's normal set point
-As the levels are restored, less insulin is secreted so that the levels don't continue to decrease |
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Inbetween a meal=Hypoglycaemia1
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-Glucagon is secreted by the alpha cells because B.G levels are too high
-travels to the liver and muscle via blood stream |
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Inbetween a meal=Hypoglycaemia2
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-Binds with cyclic-AMP as a secondary messenger
-Converts glycogen to glucose -Forms glucose from fats, glycerol and proteins from cells -Increases the level of B.G -As the levels are restored, less glucagon is secreted so that the levels don't continue to increase. |
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Hormones
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-Chemical signals produced by animals
-Made by the Endocrine Glands which secrete them directly into the bloodstream |
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Steroid Hormones
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-Soluble in lipids therefore they pass through the plasma membrane
-Oestrogen, testosterone and steroids -They don't need secondary messengers |
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Amino acid/polypeptide Hormones
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-Can not pass through the membrane
-Join to a receptor protein on the surface which then passes the signal to a secondary messenger within the cell -Insulin, glucagon |
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Cyclic AMP-Secondary Messenger
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-Protein messenger binds to a receptor on the plasma membrane
-This activates c-AMP which activates a number of enzymes in the cytoplasm which result in a cellular response |
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Cyclic AMP-Secondary Messenger 2
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-After the cell has responded, intracellular enzymes break down c-AMP
-The duration of the responses are short lived -Other secondary messengers: protein kinases, calcium ions,c-GMP |
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Steroid Hormones 2
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-Inside the cytoplasm, they bind with a Protein receptor
-The hormone-receptor protein complex moves inside the nucleus -Interacts with the cell's DNA and switches a gene on or off |
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Steroid Hormones 3
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-This changes the cell's functioning
-The response is slow but is long-lasting |
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Homeostasis
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Maintaing a relatively stable internal environment within narrow limits despite external environmental changes
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Negative Feedback
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Negative feedback occurs where the response cancels or counteracts the stimulus and it restores the internal environment back to a constant set of conditions
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Signal Transduction
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Is how the message or signal is passed along to bring about a change (response) in cell metabolism
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Signal Transduction pathway through a cell 1.
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Signal molecule is detected by a receptor protein located on the cell membrane
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Signal Transduction pathway through a cell 2.
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A message is sent via intracellular proteins to the target proteins
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Signal Transduction pathway through a cell 3.
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Target proteins are activated and will lead to a cell response
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Signal Transduction pathway through a cell 4.
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-Enzymes are activated to alter the metabolic pathways of a cell
-Change gene expression within a cell |
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Diabetes type 1
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-When the body fails to produce the signal molecule- INSULIN
-Glucose can not enter the cells so it remains in the blood and is secreted via the urine |
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Diabetes type 2
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-When target cells do not respond to insulin adequately
-Due to an ineffective receptor protein which does not bind to the insulin -Can't inject insulin |
