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58 Cards in this Set
- Front
- Back
which three G.I. hormones are produced by the stomach?
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Gastrin, somatostatin, and ghrelin
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in which part of the stomach is gastrin produced?
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Antrum
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is gastrin also produced anywhere other than the Antrum?
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yes the pancreas
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what four things stimulate the G cells of the antrum to produce gastrin?
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Vagus nerve(acetylcholine), alkali gastric content, calcium, and ethanol
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wwhat does gastrin then do?
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Gastrin acts on the parietal and chief cells, to promote HCl, intrinsic factor, and pepsinogen release
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which pathway is used by gastrin upon binding to parietal cells?
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PIP-DAG pathway, leading to increased intracellular calcium, which activates protein kinase C
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which pathway is used by histamine upon binding to parietal cells?
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c AMP pathway
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which four conditions will give an increase in gastrin levels, as well as an increase in gastric acidity?
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Gastronoma, G cell hyperplasia, retained Antrum, and renal failure
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which four conditions will give an increase in gastrin levels but normal gastric acidity?
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Post-vagotomy, chronic gastritis, pernicious anemia, and medical acid suppression
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where are most gastrinomas located?
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head of the pancreas
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what is the effect of secretin on gastrin levels?
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secretin decreases gastrin levels
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what levels of gastrin are diagnostic of gastronoma?
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Gastrin levels greater than 1000, or greater than 200 after a secretin stimulation test
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what is the single best test for localizing a gastrinoma?
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Somatostatin receptor scintigraphy
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what are the symptoms of gastrinomas?
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ulcers and diarrhea. the diarrhea here is due to lipases broken down by the increased acidity
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what is the association between gastrin and calcitonin?
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Gastrin triggers calcitonin release in medullary thyroid cancer
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what are the side effects of vagotomy?
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Decreased receptive relaxation, causing increased liquid emptying, as well as decrease solid emptying. Symptoms therefore most commonly include diarrhea but also dumping syndrome
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how effective is dietary changes in control of the dumping syndrome post vagotomy?
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very effective
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what procedure increases emptying of solids?
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pyloroplasty
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what is the role of ghrelin?
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increases appetite
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which three G.I. hormones are produced by the duodenum?
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gastric inhibitory peptide GIP, CCK, and secretin
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which cells produce GIP?
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K cells
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what does GIP do?
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decrease gastrin release, decreased insulin release
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which cells produce CCK?
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I cells
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what does CCK do?
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increased gallbladder contraction, relax sphinter of Oddi, increase pancreatic enzyme secretion
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which cells produce secretin?
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S-cells
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what does secretin do?
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Increase pancreatic bicarb release
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which for G.I. hormones are produced by the small bowel?
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moyilin, bombesin ( gastrin releasing peptide), peptide YY, and enteroglucagon
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what does motilin do?
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stimulate the migrating motor complex (MMC)
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what are the four phases of the MMC?
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phase 1 through four, quiescence, acceleration, peristalsis, deceleration
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what is the length of each MMC cycle?
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90 min.
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which part of the G.I. tract does the MMC span?
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stomach to terminal ileum
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what does bombesin do?
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bombesin, aka gastric release peptide, increases gastrin secretion, motility, and enzyme secretions
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in which part of the small bowel is peptide YY made?
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Terminal ileum
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what does peptide YY do?
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opposite effect of GRP, decreases gastrin secretion, motility and enzyme secretions
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which cells produce enteroglucagon?
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L-cells of the small bowel
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what does into enteroglucagon do?
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increase insulin release in response to luminal glucose and fat
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what is the effect enteroglucagon after small bowel resection?
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causes small bowel mucosal hypertrophy
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which four hormones are made by the pancreas?
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insulin, glucagon, vasoactive intestinal peptide VIP, and pancreatic polypeptide
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which cells produce insulin?
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Beta cells
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what is the most common islet cell tumor of the pancreas?
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Insulinoma
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what are the symptoms of insulinomas? (aka Whipple's triad)
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hypoglycemia, symptoms of hypoglycemia, and relief of symptoms after correction of hypoglycemia
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where in the pancreas are insulinomas most commonly located?
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they occur evenly throughout the pancreas
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are insulinomas benign or malignant?
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most are benign
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what is the insulin to glucose ratio in insulinomas?
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Greater than 0.4
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which cells produce glucagon?
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A cells
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what are the symptoms of glucagonomas?
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Symptoms similar to diabetes mellitus, but also dermatitis (necrolytic migratory erythema)
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how is the diagnosis of glucagonomas made?
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fasting glucagon level
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in which part of the pancreas are glucagonomas is most commonly located?
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distal pancreas
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what does vasoactive intestinal peptide do?
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Increases intestinal secretions
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are VIPomas confined to the pancreas?
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No, they can occur extra pancreatically, like in the thorax
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what are the symptoms of VIPomas (aka Verner-Morrison syndrome)?
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watery diarrhea
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what does pancreatic polypeptide do?
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Decreases intestinal secretions
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what is bile mainly made of?
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mostly bile salts, but also lecithin and cholesterol
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how is bile concentrated in the gallbladder?
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Active reabsorption of sodium, chloride, and therefore water which follows
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what is the approximate quantity of the body's pile pool?
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5g
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approximately how much bile do we lose daily?
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0.5g or 10% of the total bile pool
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How often is the bile pool recirculated?
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every 4 hours
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What are the primary bile acids?
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Cholic acid and Chenodeoxycholic acid.
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