The pancreas Flashcards
where can the pancreas be found anatomically
vertebral level L1/L2
what is acinar secretion controlled by
duodenal neuroendocrine cell secretion
in histology of the pancreas how do acinar cells present
darkest pink
what are the main 4 cell types of the endocrine pancreas
Alpha cells
Beta cells
Delta cells
F cells
How many cell types make up the endocrine pancreas
4
the 4 main cell types that make up the endocrine pancreas form structures called what
islets of langerhans
what do A (alpha) cells secrete
Glucagon
What do B (beta) cells secrete
Insulin
WHat do D (delta) cells secrete?
Somastatin
WHat do F cells secrete
pancreatic polypeptide
in histology what do the islet of langerhans look like
like an island of endocrine tissue sitting ina sea of exocrine tissue
Insulin gene encodes what
preproinsulin
what happens to preproinsulin
cleaved to the bioactive peptide, insulin, in secretory granules
final cleavage of insulin produces equimolar amounts of what
C peptides
where are the three sites of insulin synthesis
ER
Golgi
trans-golgi
what is the stimulus for beta cells to secrete insulin
rising levels of glucose
when glucose levels rise in the blood, it begins to make its way into beta cells through what
GLUT 2
what channel in insulin release does ATP inhibit
K channel
in insulin release what does M3R do
Increase ca2+ levels
what inhibits insulin release
noradrenaline, adrenaline
somastatin
no insulin is produced when plasma glucose is below…
2.8mmol-1
What does the glucagon gene encode
preproglucagon
Glucagon causes release of what other hormone
glycogen
preproglucagon is secreted from what
secretory granules
in normal/high glucagon release, what transporter helps glucose into the cell
GLUT1
The presence of glucose (in normal/high glucagon release) activates it to change to GDP and then to
ATP
In normal/high glucagon release, what causes the K+ channel to stay closed
ATP presence
ATP is constantly sending a depolarisation message
in normal/high glucagon release glucagon wnt undergo
exocytosis
in low glucagon release there is a reduction in
low extracellular plasma glucose concentration
ain low glucagon release, a reduction in extracellular plasma glucose concentration will result in
low intracellular ATP concentration
in low glucagon release, low intracellular ATP concentration causes what
inhibition of channels is relieved so K+ channel will open, allowing for hyperpolarisation of K+
in low glucagon release what does the hyperpolarisation of K+cause
allows Ca2+ to enter the cell down its concentration gradient
in low glucagon release, when Ca2+ enters the cell down its concentration gradient, what does this cause
exocytosis of glucagon from secretary vesicles
in beta cells, adrenaline acts primarily on what
alpha 1 adrenoreceptors
alpha cells primarily express what
beta 2 adrenoreceptors
what condition stimulates release of glucagon
hypoglycaemia
what condition inhibits release of glucagon
hyperglycaemia
what are two water soluble hormones in the pancreas
insulin and glucagon
what is the general effect of somastatin
inhibitory
what causes decreased gut motility and secretion
somastatin
somatostatin inhibits release of what three enteroendocrine
gastrin
CCK
GIP
what inhibits release of insulin and glucagon secretion
somastatin
why are F cells released
released in response to protein rich meals, lw blood glucose
what do F cells inhibit
gall bladder contraction
pancreatic exocrine product secretion
what cell inhibits gall bladder contraction and exocrine product secretion
F cells
