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Flashcards in Pancreatic Beta Cell Deck (14)
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1

what is produced by pancreatic beta cells in the pancreatic islets

insulin

2

what is the first step of insulin secretion

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

3

what happens to glucose in the pancreatic beta cell

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

4

what does increased metabolism of glucose lead to

increase in intracellular ATP conc.

5

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

6

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.

7

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

fusion of secretory vesicles with the cell membrane and insulin secretion

8

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

9

what level of blood glucose should insulin be produced at

if rises above 5 mM

10

what happens to pancreatic beta cells in type 1 diabetes

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

11

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

12

describe the pattern of insulin secretion

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

13

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

14

what happens to insulin secretion in poorly controlled T2DM

insulin secretion weakens and flattens, not biphasic