The endocrine pancreas Flashcards
what does the pancreas develop from
outgrowth of gut tube
closely associated with the gall bladder
what do acini cells produce
pancreatic amylase
what do islets of Langerhans produce
hormones
what do alpha cells in the islet of Langerhans produce
glucagon
what do beta cells produce
insulin
what do Delta cells in the islets of Langerhans produce
somatostatin
what do F cells produce
pancreatic polypeptide (self regulates pancreatic secretions, stimulates digestive enzyme and bicarb secretion)
what factors regulate insulin release
increased blood glucose some amino acids GI tract hormones free fatty acids glucagon parasympathetic stimulation (aCh) Beta adrenergic stimulation
decrease: alpha adrenergic stimulation
delta cells/ somatostatin
insulin (-ve feeback)
what is the mechanism of insulin release
glucose enters the cell via glut2 transporter
increase glucose stimulates glucose metabolism leading to an increase in ATP
this inhibits K+ channel
this causes the cell to depolarize
this activate voltage gated calcium channel
this promotes calcium influx
this leads to exocytosis of insulin granules
what are the physiological actions of insulin
increased protein synthesis
increased glycogenesis
increased glucose transport into cells
increased lipogenesis
(think of pt with fat lumps)
what factors regulate glucagon release
certain amino acids
gi hormones
psymp stimulation
beta and alpha adrenergic stimulation
decrease:
insulin
somatostatin
what are the physiological actions of glucagon
decreased lipogenesis increased lipolysis increased free fatty acids increased glycerol increased glycogenolysis increased cortisol increased gluconeogenesis
what is glucosuria
glucose exceeds renal threshold for reabsorption
what causes polyuria in diabetes
osmotic diuresis due to glucose in tubular fluid
what causes polydipsia
dehydration increases angiotensin 2 levels which act as a dipsogen
