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24 Cards in this Set
- Front
- Back
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Role of BILE SALT in regulation of bile secretion
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Stimulates hepatic bile flow
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Role of VAGUS NERVE in regulation of bile secretion
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Gall bladder contraction
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Role of cholecystokinin and fibroblastic growth factor 19 in bile secretion
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CCK = gall bladder contraction, FGF19 = gall bladder relaxation
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2 major functions of bile
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(1) aid in digestion of FAT
(2) help liver get rid of toxins and metabolites (cholesterol, metal cations, drug metabolites, bilirubin) |
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2 major constituents of bile
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water and bile salts (+ phospholipids, bilirubin, cholesterol)
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3 major functions of bile salts
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INcrease bile flow in the liver, aid in the absorption of fats, influence CHOLESTEROL metabolism /elimination
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Bile salts are synthesized from....
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CHOLESTEROL in the liver
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2 primary bile salt forms
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Cholic acid and chenodeoxycholic acid
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How do bile salts both help with ABSORPTION and REMOVAL of cholesterol?
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Micelles surround cholesterol, increase solubility and help the cholesterol be absorbed. BUT they also are one of hte main ways cholesterol is secreted from body AND help the liver secrete cholesterol into the intestine (which goes into feces) -- due to osmotic gradient in canaliculi
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Antimicrobail actions of bile salts in PROXMIAL and DISTAL intestine
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PROXIMAL = bacteriostatic interactions with the mixed micelles, DISTAL = hormone (stimulates Paneth cells to secrete anti-microbial factors)
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Normal route of excretion of OXALATE
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Usually binds with calcium in the intestine --> crystalizes --> secreted in feces.
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What happens to oxalate when decreased calcium concentration?
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Oxalate absorbed by the intestine and filtered by the kidney. Can combine with calcium there to form oxalate kidney stones. BAD
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What happens with oxalate when there are decreased bile salt concentrations?
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Decreased bile salt concentrations = increased long chain fatty acids in the intestine (want to bind with calcium) = less calcium available to bind with oxalate = increased oxalate absorption
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Main purpose of conjugating bile salts to amino acids (glycine and taurine)
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Keeps them SOLUBLE within the GI tract (increases aqueous solubility)
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What converts primary bile salts to secondary bile salts?
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Intestinal bacterial flora
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What process does the bile salt undergo by bacteria flora?
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Dehydroxylation
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How much bile salt is EXCRETED vs. REABSORBED?
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5% excreted, 95% reabsorbed
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Where does bile salt reabsorption take place
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In the ileum
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Where are bile salts stored AFTER cholecysectomy?
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IN the small intestine
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Main mechanism behind gall stones (too much/too little...)
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Too much cholesterol in bile (precipitates out)
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Role of bile in preventing gall stones
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Bind and solubilize CHOLESTEROL + bind calcium and prevent formation of calcium salts (insoluble precipitates)
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What are symptoms of defects in bile salt synthesis and conjugation?
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Cholestasis, malabsorption of Vitamins A, D, E, K
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Mechanism of Progressive Famalial Intrahepatic Cholestasis
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defective membrane transport of bile salts through hepatocytes and enterocytes (causes jaundice and colestasis + diarrhea and malabsorption)
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What conditions are ursodeoxcycholic acid used to treat?
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Primary biliary cirrhosis, cholestasis of pregnancy, gall stones
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