Pancreatic Beta Cell Flashcards Preview

ENDO > Pancreatic Beta Cell > Flashcards

Flashcards in Pancreatic Beta Cell Deck (14)
Loading flashcards...

what is produced by pancreatic beta cells in the pancreatic islets



what is the first step of insulin secretion

glucose enters beta cell, when conc. increases, via GLUT2 transporter


what happens to glucose in the pancreatic beta cell

it is phosphorylated by glucokinase, to produce glucose-6-phosphate


what does increased metabolism of glucose lead to

increase in intracellular ATP conc.


what does ATP inhibit in the pancreatic beta cell, and what does this lead to

ATP sensitive K+ channel Katp, leads to depolarisation of the cell membrane


what is the result of the depolarisation of the cell membrane of the pancreatic beta cells

opening on the voltage gated Ca2+ channels, increasing intracellular Ca2+ conc.


what does an increase in intracellular Ca2+ conc. lead to

fusion of secretory vesicles with the cell membrane and insulin secretion


what is the amount of insulin released from the pancreatic beta cell directly related to

the amount of glucose that has entered the cell and has been phosphorylated


what level of blood glucose should insulin be produced at

if rises above 5 mM


what happens to pancreatic beta cells in type 1 diabetes

autoimmune attack on them, most are lost and don't secrete insulin


describe the effect on pancreatic beta cells in forms of diabetes where they are still present

cells lose ability to respond to changes in glucose due to hyperglycaemia glucose conc. outwith the Km of glucokinase


describe the pattern of insulin secretion

biphasic, the first wave to prevent sharp increase in blood increase, the second more tuned to insulin needs


describe why there are 2 phases of insulin secretion

5% of insulin is immediately available - RRP, readily releasable pool
Reserve pool of insulin needs to undergo other reactions/signals to become mobilised


what happens to insulin secretion in poorly controlled T2DM

insulin secretion weakens and flattens, not biphasic