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16 Cards in this Set
- Front
- Back
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apical end of hepatocyte communicates with...
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canaliculus
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contents in canaliculi
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bile
cellular & paracellular transportation of water bicarb (micelle formation, neutralize stomache acid, increase sol of bile acid & salt) |
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transport in bile secretion
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Na/K ATPase (side, Na out)
draws Na in from sinus bile salt follows combines with protein ATPase pumps into canaliculus |
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control gate for secretion of bile
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sphincter of Oddi
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components of bile
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Bile salts- 65%
Phospholipids (20%) -lecithin (phosphotidyl choline) cholesterol proteins bilirubin |
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transporters in bile concentration
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in gallbladder
Na/K pump (side) drives Na out (to interstitium) Na in from lumen (H+ out) Cl follows & draws water from lumen to interstit via tight jctn Cl/HCO3 at lumen (Cl in) |
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stimulation of bile release from gallbladder
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enteroendocrine sense FA's >8 c's in length
release CCK into blood binds sm musc cells around Oddi & GB Oddi relax, GB contract |
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bile is recycled via...
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enterohepatic circulation
2-3 times/meal only 10-20% excreted/day |
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bile returned to liver by...
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hepatic portal veins
Na dependent R's in terminal ileum |
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bile acid
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derivitive of cholesterol
less soluble than bile salt has OH |
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characteristics of bile salt
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more completely ionized at neutral pH
more soluble than bile acid has Glycine or Taurine via peptide bond |
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formation of bile
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cholesterol
7 alpha hydroxylase is rate limit step 7 hydroxychol can become cholyl CoA conjugated to glycocholic or taurocholic acid in liver |
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stability of bile acids
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glycocholic acid pKa 3.7
Taurocholic acid pKa 1.5 (more soluble) |
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function of bile
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emulsify fat
increase surface area of lipid for lipase to work on |
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formation of micelle
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bilipid layer
polar group on outside hydrophobic inside (happens b/c increased entropy) |
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unstirred water layer
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b/c of micelles
allows polar portion to approach lipid (nonpolar) held near for absorption |
