PHSI 208 Lecture Notes - Lecture 7: Critical Micelle Concentration, Bile Acid, Colipase
Document Summary
Review the contributions of the biliary secretions to digestion. Know the cell types responsible for liver functions. Liver secretions: primary bile acid: bile acid conjugated with taurine and glycine. Makes up 50% of bile: secondary bile acid: colonic bacteria enzymes convert or deconjugate primary bile acids to secondary. Gallbladder fxns: storage and concentration of bile (5 10x from absorption of water) by receptive relaxation (no-mediated). Bile from the gallbladder aids digestion, but is not essential for it, as liver keeps slow constant discharge of bile into the duodenum. Fatty acids and proteins in the duodenum cause release of cck (cholechystokinin). Production of bile is increased by stimulation of the vagus nerves, and by the hormone secretin. Dietary fat as large triglyceride droplets trigger cck release, leading to contraction of the gallbladder which releases bile salts to dissolve fat droplets. They promote transfer of lipid by-products to epithelial cells.
