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7 Cards in this Set
- Front
- Back
Pancreatic enzyme
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Typsin, chymotrypsin, elastase
Carboxypeptidase Amylase Lipase Ribonuclease, deoxyribonuclease |
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Control of pancreatic exocrine secretion
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Most important: intestinal phase
1. Acid chyme in duodenum --> secretin from S cells --> secretion of HCO3- rich fluid 2. Partially digested protein and fat in duodenum --> CCK from I cells --> secretion of pancreatic enzyme Vagal (cephalic phase), CCK and secretin are synergistic |
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Functions of biliary secretions
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Digestive functions:
Bile acids: 1. Emulsification and formation of micelles 2. Aid fat digestion and absroption 3. Promote absorption of fat soluble vitamins HCO3-: Neutralize acidic chyme and provide optimal pH for enzyme action Excretory functions 1. Bile pigment 2. Excess cholesterol 3. Drugs |
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Contents of bile
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Water, electrolytes, organic molecules (bile acids, cholesterol, phospholipids, bilirubin)
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Control of biliary secretion
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Most potent: bile acids - bile acid in blood stimulate uptake and re-secretion of bile acids, inhibts hepatocyte synthesis of bile salts
Secretin: stimulate secretion of HCO3- rich fluid, stimulated by acidic chyme in stomach CCK: stimulate contraction of gallbladder and relaxation of sphincter of Oddi, fat and peptides in duodenum stimulates CCK release Vagus: stimulate contraction of gallbladder |
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2 stages of biliary secretion
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1. First stage: Hepatocyte secret fluid rich in bile salts, cholesterol and other organic components into canaliculi
2. Second stage: bile flows through bile duct, modified by addition of watery, bicarbonate-rich secretion from ductal epithelial cells 3. Bile stored and concentreated in gallbladder through absorption of water, sodium, chloride and other electrolytes |
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primary and secondary bile salt
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primary: cholic acid, chenodeoxycholic acid
Intestinal bacteria change to secondary bile acid by dehydroxylation both conjugated with glycine and taurine |