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19 Cards in this Set
- Front
- Back
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Endocrine cells within the gut |
- endocrine cells of GEP (gastroentero-pancreatic) system - open configuration (sensitive to contents -> hormone release into blood) [--pancreas & oxynthic region of stomach] + NS's: extrinsic (PS, S) & intrinsic (enteric - submucosal & intermuscular) + SM's |
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Gut Hormones |
Secretins - secretin, VIP, GIP, glucagon, GLP-1, bombesin (GRP - vagal transmitter -> gastrin release) Gastrins - gastrin, CCK (major: 33 AA's), motilin, encephalin (, cerulean) - size heterogeneity; amide essential + PP, Somatostatin (SRIH), urogastrone, chymodenin, tachykinins |
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Gastrin forms |
Secreted from G cells (pyloric antrum of stomach), duodenum, pancreas 4 major forms (each in non- & sulfated form) Component I ~ preprogastrin (70 AA's) G34 - "big gastrin" (34 AA's) G17 - "little gastrin" (17 AA's) - major form G14 - "mini gastrin" (14 AA's) -- all have common N terminus (active part) |
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Gastrin effects |
Acts synergistically w/ Ach (<- vagal impulses) & histamine (-> type 2 H-R; |-- cymetidine [ulcers]) - oxynthic cells -> gastric A; chief cells -> pepsinogen (indirectly) - mucosa of the stomach -> trophic action (-> growth) - gastric motility |
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Gastrin regulation |
++ Vagal activity -> via GRP (bombesin) ++ Peptides AA's (Trp, Phe, Arg), Ca++ in chyme - - A ~ pH < 3.5 -> via somatostatin (-fb) - - secretin (& CCK) |
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Zollinger-Ellison Syndrome (ZE) |
Gastrin hypersecretion from - pancreatic islet tumors (= gastrinomas, spread out) - hyperplastic mucosal G cells -> ulcerative disease, gastric mucosa overgrowth - secretin -> ↑gastrin (! diagnostic test) |
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CCK (Cholecystokinin) effects |
- released in duodenum - gall bladder -> contration - sphincter of Oddi -> relaxation --| (competitive) gastrin-induced A secretion (neutralization activity) - pancreas -> proenzyme release (active at neutral pH) - pancreas (acinar cells) -> synergictic action w/ secretin, Ach -> HCO3-/H2O release |
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CCK regulation |
++ Peptides & AA's (Trp, Phe, Val, Leu, Met) in chyme
++ Fats, acidity (weak) |
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Secretin effects |
Secreted by S cells in jejunum & duodenum - synergictic action w/ CCK (neutralization): -- pancreas (acinar cells) -> enzymes & HCO3-/H2O release -- bile flow & composition (↑[HCO3-/H2O]) --| gastrin release (& stomach A secretion) |
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Secretin regulation |
++ A in duodenum - - Ach (vagal) |
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GLP-1 (Glucagon-Like Peptide 1) |
- produced by intestinal L-cells - 30 AA's - pancreas -> insulin (in response to oral glucose) --| gastric secretion & emptying [anorexogenic, T2DM] |
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Ghrelin |
- released upon fasting & insulin-induced hypoglycemia (E insufficiency) in GI tract -> eating (orexogenic) - 28 AA's - brain/gut peptide (GHRP): -> GHRH -> GH --| somatostatin -> pituitary -> somatotrophs |
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Leptin & Adiponectin |
- proteins of adipose tissue in response to E sufficiency -> cell surface R's --| hunger (anorexogenic) - ↑ insulin responsiveness in T2DM |
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VIP (Vasoactive Intestinal Peptide) |
- colon, ileum, jejunum, pancreas, neurons (NT?) - released from duodenum in response to HCl/fat -> sphincter relaxation (w/ NO) --| A secretion, motility, gall bladder contraction - intestine & pancreas -> H2O & electrolyte secretion from mucosa - secreting tumor = VIPoma -> watery-diarrhea syndrome |
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[GIP (Gastric Inhibitory Polypeptide)] |
Plasma glucose -> insulin secretion |
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Somatostatin |
NT released from (hypothalamus,) pancreatic D-cells & gastric mucosa in response to A --| insulin, glucagon, gastric A, gastrin (-fb), secretin, CCK, GIP, VIP, motilin |
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[Urogastrone] |
= epidermal GF - also in submaxillary glands & Brunner's glands of the duodenum --| A secretion |
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[Enkephalin] |
= immunoreactive (Met)enkephalin (opioid-R ligand) in antral stomach, duodenum, ileum, colon, gall bladder, pancreas - inhibitory |
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[Peptide YY] |
- contains Tyr residues - 18/36 AA's = pancreatic polypeptide - released in response to fat --| gastric secretion & emptying (vagal effects) |
