5.2 insulin & glucagon Flashcards
where is insulin produced?
Beta cells in the islets of langerhan
when is insulin produced?
when blood glucose levels are too high
at what point are blood glucose levels too high?
over 90cm mg-3
what do beta cells detect?
rises in blood glucose levels
where do beta cells secrete insulin?
into the bloodstream
virtually all body cells have receptors for insulin, which body cells don’t?
red blood cells
they have no organelles
what type of receptor does insulin bind to?
glycoprotein receptor
what does insulin cause when it binds to the glycoprotein receptor? what effect does it have?
causes change in tertiary structure of glucose transporter protein channels
allows more glucose in
insulin lowers blood glucose by increasing absorption in what?
cells
insulin lowers blood glucose by increasing what else in cells?
respiration
insulin also lowers blood glucose levels by increasing the rate of which G?
glycogenesis
what is glycogenesis?
converting excess glucose into glycogen to be stored in liver
insulin lowers blood glucose by increasing conversion of what?
glucose to fat
insulin lowers blood glucose by inhibiting the release of what?
glucagon
where is glucagon produced?
alpha cells of the islets of langerhan
when is glucagon produced?
when blood glucose levels fall
where do alpha cells secrete glucagon?
into the blood stream
which cells have glucagon receptors?
liver and fat cells
glucagon raises blood sugar by breaking down glycogen, what is this?
glycogenolysis
glucagon also increases gluconeogenesis, what is this?
producing glucose from non carbohydrate sources e.g. lipids and amino acids, then releasing it into the blood stream
what does negative feedback ensure?
changes are reversed and returned back to a set level
