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45 Cards in this Set
- Front
- Back
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What is the product of a gastric parietal cell? |
- HCl - Intrinsic factor |
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What is the product of a chief cell? |
PEPsinogen (think "a PEPpy cheif") |
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What is the product of a G cell? Location? |
Gastrin, G cells are found in the antrum |
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What is the product of a mucus neck cell? |
Bicarbonate mucus |
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What is pepsin? |
Proteolytic enzyme that hydrolyzes peptide bonds |
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What is intrinsic factor? |
Protein secreted by the parietal cells that combines with vitamin B12 and enables absorption in the terminal ileum |
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Name three receptors on the parietal cell that stimulates HCl release? |
HAG: 1. Histamine 2. Acetylcholine 3. Gastrin |
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What is the enterohepatic circulation? |
Circulation of bile acids from the liver to the gut and back to the liver via the portal vein |
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Where are most of the bile acids absorbed? |
Terminal ileum |
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How many times is the entire bile acid pool circulated during a typical meal? |
Twice |
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What are the stimulators of gallbladder emptying? |
- Cholecystokinin - Vagal input |
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What are the inhibitors of gallbladder emptying? |
- Somatostatin - Sympathetics (impossible to flee and digest food simultaneously) - Vasoactive intestinal polypeptide (VIP) |
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What is the source of cholecystokinin? |
Duodenal mucosal cells |
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What stimulates the release of cholecystokinin? |
- Fat - Protein - Amino acids - HCl |
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What inhibits the release of cholecystokinin? |
- Trypsin - Chymotrypsin |
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What are the actions of cholecystokinin? |
- Empties gallbladder - Opens ampulla of Vater - Slows gastric emptying - Stimulates pancreatic acinar cell growth and release of exocrine products |
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What is the source of secretin? |
Duodenal cells (specifically the argyrophilic S cells) |
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What stimulates the release of secretin? |
- pH <4.5 (acid) - Fat in the duodenum |
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What inhibits the release of secretin? |
High pH in the duodenum |
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What are the actions of secretin? |
- Releases pancreatic bicarbonate / enzymes / H2O - Releases bile / bicarbonate - Decreases lower esophageal sphincter (LES) tone - Decreases release of gastric acid |
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What is the source of gastrin? |
Gastric antrum G cells |
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What stimulates release of gastrin? |
- Stomach peptides, amino acids - Vagal input - Calcium |
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What inhibits the release of gastrin? |
- pH <3.0 - Somatostatin |
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What are the actions of gastrin? |
- Release of HCl from parietal cells - Trophic effect on mucosa of the stomach and small intestine |
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What is the source of somatostatin? |
Pancreatic D cells |
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What stimulates the release of somatostatin? |
Food |
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What are the actions of somatostatin? |
Globally inhibits GI function |
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What is the purpose of the colon? |
Reabsorption of H2O and storage of stool |
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What is the main small bowel nutritional source? |
Glutamine |
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What is the main nutritional source of the colon? |
Butyrate (short-chain fatty acid) |
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Where is calcium absorbed? |
Duodenum actively; jejunum passively |
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Where is iron absorbed? |
Duodenum |
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Where is vitamin B12 absorbed? |
Terminal ileum |
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Which hormone primarily controls gallbladder contraction? |
CCK |
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What supplement does a patient need after removal of the terminal ileum or stomach? |
Vitamin B12 |
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Name the main constituents of bile? |
- Water - Phospholipids (lecithins) - Bile acids - Cholesterol - Bilirubin |
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What are most gallstones made of? |
Cholesterol |
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How do opiates affect the bowels? |
By stimulating sodium absorption and inhibiting secretion in the ileum as well as decreasing GI motility by incoordinated peristalsis
Therefore, place patients on stool softeners when dispensing pain meds |
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Which type of muscle fibers, smooth or striated, does the esophagus contain? |
- Upper 1/3: striated muscle control of motor nerves - Middle 1/3: mixed - Lower 1/3: smooth muscle primarily under control of vagal motor fibers |
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Which electrolytes does the colon actively absorb? |
Na+, Cl- |
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Which electrolyte does the colon actively secrete? |
HCO3- (plays a role in diarrhea causing the patient to have a normal anion gap acidosis) |
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Which electrolytes does the colon passively secrete? |
K+ |
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What ist he gastrocolic reflex? |
Increased secretory and motor functions of the stomach result in increased colonic motility |
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What is the blood supply to the liver? |
- 75% from portal vein, rich in products of digestion - 25% from hepatic artery, rich in O2 (but each provide for 50% of O2) |
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What are Peyer patches? |
Nodules of lymphoid tissue with B and T lymphocytes in small intestine that selectively sample lumenal antigens found in the terminal ileum |
