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Where is the pancrease located?
In the curve of the duodenum, the first part of the small intestine.
What are the 3 parts of the pancrease?
The head, body and tail
What are the cells of the pancrease arranged in?
clusters called acini
What do the acini produce?
What are scattered among the exocrine acini?, 1-2 million tiny clusters of endocrine tissue..
pancreatic islets or islets of langerhans
Each pancreatic islet includes four types of hormone-secreting cells called:
Alpha or A cells
Beta or B cells
Delta or D cells
Define Alpha cells
constitute about 17% of pancreatic islet cells and secrete glucagon
Define Beta cells
constitute about 70% of pancreatic islet cells and secrete insulin
define Delta cells
constitute about 7% of pancreatic islet cells and secrete somatostatin (identical to the growth hormone inhibiting hormone secreted by the hypothalamus)
Define F cells
constitute the remainder of pancreatic islet cells and secrete pancreatic polypeptide.
What does glucagon do?
Raises blood glucose level
what does insulin do?
lowers blood glucose levels
the somatostatin from the pancrease does what?
acts in a paracrine manner to inhibit both insulin and glucagon release from neighboring beta and alpha cells. May also act as a circulating hormone to slow absorption of nutrients from the gastrointestinal tract.
What does pancreatic polypeptide do?
inhibits somatostatin secretion, gallbladder contraction, and secretion of digestive enzymes by the pancreas.
The level of blood glucose controls secretion of ____ and ____ via ____ ___.
- negative feedback
Does glucagon stimulate insulin release directly or indirectly?
What does insulin do to glucagon?
it suppresses glucagon secretion
Alpha cells of the pancreas are released from the ____ effect of insulin so they can secrete more ____
Why does hGH and ACTH stimulate secretion of insulin?
because they act to elevate blood glucose
Other than hGH and ACTH and beta cells, what else can stimulate insulin secretion?
amino acids, arginine and leucine
glucose dependent insulinotropic peptide (GIP) - a hormone released by enteroendocrine cells of the small intestine in response to the presence of glucose in teh gastrointestinal tract
What is glucagon secretion stimulated by?
increased activity of the sympathetic division of the ANS, as occurs during exercise
A rise in blood amino acids if blood glucose level is low, which could occur after a meal that contained mainly protein