CONTROL OF BLOOD GLUCOSE

Question 1

what is negative feedback?

Answer 1

when any deviation from the normal values are restored to their original level (homeostasis)

Question 2

what role does the pancreas play?

Answer 2

detects changes in the blood glucose concentration by using endocrine cells in the ISLETS OF LANGERHAN, b cells and a cells, which release insulin and glucagon

Question 3

what is the effect of adrenaline?

Answer 3

more glucose is being released to increase blood glucose conc, more glycogenosis.

Question 4

how is increased blood glucose concentration managed?

Answer 4

beta cells release insulin, to convert glucose into glycogen

Question 5

how does blood glucose conc increase in cells when insulin is secreted?

Answer 5

-insulin binds to insulin receptors
-causing chemicals to released within the cells
-chemicals cause the vesicles to move up and fuse to membrane
vesicles contain protein channels that glucose can pass through
-protein channels are embedded in cell surface membrane
-surface is more permeable to glucose diffusion

Question 6

how is low blood glucose conc managed?

Answer 6

detected by alpha cells which secrete glucagon and adrenal glands secrete adrenaline to stimulate glycogenolysis

Question 7

what is the action of glucagon?

Answer 7

-attaches to complementory receptors on liver cells
-causes protein, adenylate cyclase, to convert ATP into cAMP
-cAMP activates protein kinase which stimulates glycogenolysis

Question 8

how does adrenaline increase blood glucose conc?

Answer 8

-attaches to receptors on the surace of liver cells
-G protein activates conversion of ATP into cAMP
-cAMP activates enzyme needed to convert glycogen into glucose