NUSCTX 103 Lecture Notes - Lecture 4: Enterohepatic Circulation, Portal Vein, Bile Acid
6 Jan 2020
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Amphipathic (polar/charged +/- & nonpolar side: know how bile salt mixed micelles and the unstirred water layer (uwl) influence absorption of lipids across the brush border membrane. Bile salt mixed micelles provide hydrophilic/polar region to pass through uwl (hydrophobic/nonpolar) & be digested in enterocyte: know by which mechanisms lipid constituents are transported across the brush border membrane. Know the main transporters for cholesterol (& plant sterols) and fatty acids. What enzymes are involved? (fa & glycerol [other components of lipids] reform/reassemble lipids) Breakdown tag: gastric lipase: tag > 1,2-dag + sn-3 fa (pancreatic lipase: tag (or 1,2-dag) > 2-mag + 2 (or 1) ffa *sn-1 & sn-3 ) Pancreatic lipase: tag > 2-mag + sn-1, sn-3 (2) ffas: lc fa + coenzyme a (acyl-coa synthetase acs ; mg & atp)--> long-chain fatty acyl- [pro]phospholipase a2: phosphatidylcholine > lysophosphatidylcholine + (sn-2) ffa. Where: formed in er lumen > exocytosed from basolateral membrane of.
