exam 2: insulin Flashcards
fendocrine pancreas. is 1%
islet of Langerhan cells:
A cells secrete=
B cells secrete=
D cells= (inhibitor)
F cells=
A cells secrete= glucagon
B cells secrete=insulin
D cells secrete= somatostatin (inhibits A and B cells)
majority of the islets of langerhan cells:
a and B cells
exocrine portion of pancreas is what releases _____ enzymes into the lumen of the small intestine
digestive
a and b cells go into_____ (why called endocrine)
into blood
majority of the pancreas is ____ cells that are moved into duadumen for digestion
acinar cells
insulin secretion is associated with
energy abundance
insulin is composed of two amino acid chains, connected by:
disulfide linkages
and a and b chains
when a and b chains are split in insulin, functional activity of insulin molecule is
lost
what have virtually no insulin activity
proinsulin and C peptide
formation of insulin occurs in ___ cells. it is first made as:
Beta cells
first made as proinsulin
in the golgi, proinsulin is cleaved to form
c peptide and insulin
insulin circulates entirely in
unbounded form
what is the key regulator of insulin secretion
glucose
when glucose levels ____, this stimulates insulin synthesis
increase (>3.9 mmol/L)
mechanism of insulin secretion.
- glucose enters cell _____ concentration gradient
- glucose is metabolized until it produces:
- when ATP ______, this _____ the SUR channel (sulfonylurea receptor channel)
- this causes depolarization of:
moving it: - causes Ca2+ channel to:
exocytosis - this kinda pushes the reaction onward and increases levels of cAMP
- exocytosis of
- down (high to low)
- ATP
- closes channels (it is a K+ gated channel gated by the presence of ATP) aka high atp=closed channel
- depolarization of K+ moving it away from its equlibrium
- Ca2+ channel opens (exocytosis)
- incretins
- exocytosis of insulin!
for treatment for _______, some medications close the SUR channel
type 2 diabetes mellitus
hormones produced by the digestive system that work to stimulate insulin secretion BEFORE plasma glucose is elevated.
GLP-1 and GIP
incretins
ozempic!!
normal fasting blood glucose is _______mg/100ml
80-90mg/100 ml
insulin secretion rises when blood glucose rises above
100 mg/100ml