Anatomy 2

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Anatomy 2
2011-01-30 16:13:41
Pancreatic Islets Pg

Pancreatic Islets
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  1. Where is the pancrease located?
    In the curve of the duodenum, the first part of the small intestine.
  2. What are the 3 parts of the pancrease?
    The head, body and tail
  3. What are the cells of the pancrease arranged in?
    clusters called acini
  4. What do the acini produce?
    digestive enzymes
  5. What are scattered among the exocrine acini?, 1-2 million tiny clusters of endocrine tissue..
    pancreatic islets or islets of langerhans
  6. Each pancreatic islet includes four types of hormone-secreting cells called:
    Alpha or A cells

    Beta or B cells

    Delta or D cells

    F cells
  7. Define Alpha cells
    constitute about 17% of pancreatic islet cells and secrete glucagon
  8. Define Beta cells
    constitute about 70% of pancreatic islet cells and secrete insulin
  9. define Delta cells
    constitute about 7% of pancreatic islet cells and secrete somatostatin (identical to the growth hormone inhibiting hormone secreted by the hypothalamus)
  10. Define F cells
    constitute the remainder of pancreatic islet cells and secrete pancreatic polypeptide.
  11. What does glucagon do?
    Raises blood glucose level
  12. what does insulin do?
    lowers blood glucose levels
  13. 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.
  14. What does pancreatic polypeptide do?
    inhibits somatostatin secretion, gallbladder contraction, and secretion of digestive enzymes by the pancreas.
  15. The level of blood glucose controls secretion of ____ and ____ via ____ ___.
    • glucagon
    • insulin
    • negative feedback
  16. Does glucagon stimulate insulin release directly or indirectly?
  17. What does insulin do to glucagon?
    it suppresses glucagon secretion
  18. Alpha cells of the pancreas are released from the ____ effect of insulin so they can secrete more ____

  19. Why does hGH and ACTH stimulate secretion of insulin?
    because they act to elevate blood glucose
  20. 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
  21. 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