Homeostasis: Control of Blood Glucose Concentration (BGC)
- Created by: evaabarry
- Created on: 02-03-22 09:03
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- Homeostasis:Control of blood glucose concentration (BGC)
- Should remain at fairly constant value - 100mg glucose per 100cm3 of blood
- IF FALLS BELOW THIS LEVEL : - Person is hypoglycaemic - Cells dont have enough glucose to carry out respiration , so metabolic reactions not able to take place in cells and cant function normally
- cells such as brain cells which can only use glucose & not other respiratory substrates. - person may become unconscious and tissues can be damaged
- IF RISES ABOVE LEVEL: - person is hyperglycaemic - High glucose concentration decreases as water potential of blood & tissue fluid. So water moves out of cells down water potential gradient. - unconsciousness can result
- IF FALLS BELOW THIS LEVEL : - Person is hypoglycaemic - Cells dont have enough glucose to carry out respiration , so metabolic reactions not able to take place in cells and cant function normally
- Several hormones involved: - INSULIN. - GLUCAGON By negative feedback
- - Both small proteins. - Secreted by patches of tissue: ISLETS OF LANGERHANS in pancreas. - INSULIN secreted by B cells. - GLUCAGON secreted by a cells
- B CELLS : Sense when BGC rises too high. - Respond by secreting greater quantities of insulin into blood.
- INSULIN HAS SEVERAL EFFECTS: (causes BGC to fall)
- - Causing muscle and adipose tissue cells (fat cells) to absorb more glucose from blood
- - Causing liver cells to convert glucose to glycogen for storage
- INSULIN HAS SEVERAL EFFECTS: (causes BGC to fall)
- A CELLS : sense when BGC falls too low. - respond by secreting greater quantities of glucagon into blood.
- SEVERAL EFFECTS :
- - Causing liver cells to break down glycogen to glucose, releasing into blood
- - Causing liver cells to produce glucose from other substrates such as amino acids or lipids
- SEVERAL EFFECTS :
- B CELLS : Sense when BGC rises too high. - Respond by secreting greater quantities of insulin into blood.
- - Both small proteins. - Secreted by patches of tissue: ISLETS OF LANGERHANS in pancreas. - INSULIN secreted by B cells. - GLUCAGON secreted by a cells
- Should remain at fairly constant value - 100mg glucose per 100cm3 of blood
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