endocrine pancreas Flashcards
what do alpha cells secrete
glucagon
what do beta cells secrete
insulin
what do delta cells secrete
somatostatin - paracrine moderator
what do PP cells secrete
pancreatic polypeptide
what do epsilon cells secrete
ghrelin
what are the islets of langerhans
clusters of 1000- endocrine cells
explain systemic glucose homeostasis and lipid homeostasis
how do beta cells work
GSIS - glucose stimulated insulin secretion
note the ready - releasable pool
explain glucose sensing in beta cells
facilitate does dependent stimulation of insulin secretion by glucose
what is the role of K ATP channel and electricity activity in beta cell glucose sensing
at low glucose = the channel is open maintaining a hyper polarised plasma membrane
at high glucose = the channel closes depolarising the PM , triggering insulin secretion
*this channel is the target of many DM drugs ie sulphonylurea ie binds to SUR1 of K ATP channel - closing it
other functions of beta cells
respond to nutrients, hormones and neurotransmitters > secrete appropriate amounts of insulin
explain beta cell failure in T2DM
insulin resistance + beta cell dysfunction = relative insulin deficiency
is insulin secretion biphasic T/F ?
T
unpeople with T2DM they have impaired first and second wave response and this can be seen very early in diabetes development
T/F diabetes go into remission with a low calorie dit
T
do you know all this
glucose sensing in alpha cells
low glucose = K ATP open
high glucose = K ATP closed
what is the role of glucagon in glucose homeostasis
glucagon in T2DM
remains high
due to lack of suppression of GCG secretion at high glucose
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what is the paracrine regulator of islet function
delta cells
-somatostatin is secreted in response to nutrient or hormonal stimulation which surpasses beta and alpha cell function in a paracrine manner
there are numerous bi-directional paracrine circuits within islets
