HNF 461 Lecture 18 Outline of Last Lecture I Dietary Guidelines II Functions of Lipids III Categorization IV Triglycerides a Most common fatty acids V Nomenclature a Naming Systems Outline of Current Lecture I Major Events of Digestion II Cholesterol Esters and Phospholipid Digestion III Micelles IV Bile V In the Cell VI Chylomicron VII Therapeutic Inhibition of Fat Absorption a Olestra sucrose Polyester b Orlistat lipase Inhibitor Current Lecture Fat Digestion and Absorption 1 Major Events of Digestion a Mouth i Minor amount of digestion from triglyceride triglycerides diglycerides and fatty acids ii Lingual Lipase produced by salivary glands b Stomach i Additional minimal digestion into triglycerides diglycerides and fatty acids These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute ii Gastric lipase produced by stomach c Small Intestine i Phase 1 Emulsification of large fat droplets emulsified triglycerides diglycerides and fatty acid micelles 1 Bile no lipase involved ii Phase II Enzymatic digestion into monoglycerides and fatty acids 1 Pancreatic lipase produced by pancreas 2 Pancreas has exocrine and endocrine function 3 NaHCO3 also produced as part of pancreatic juice neutralizes stomach acid so digestive enzymes can function in the small intestine 2 Cholesterol Esters and Phospholipid Digestion a Cholesterol Esters CE Free cholesterol and fatty acids b Phospholipids Lysophospholipids and free fatty acids by A2 enzyme 3 Micelles a Digested fat products are packed into micelles small vestibule b Contains MAG monoacylglycerol fatty acids free cholesterol lysophospholipids and bile 4 Bile a Produced from cholesterol similar in structure but bile contains COOH group b Bile acids cholesterol and phospholipids c Liver produces 2 5 g bile acids d 90 of bile acids produced are recycled back to liver by hepatic portal vein e 10 of produced cholesterol is in the bile half of which is excreted out of the body 5 In the Cell a All lipid particles are transported into the cell through some method b Fatty Acids activated by FA CoA then synthesized again mostly into triglycerides i Triglycerides synthesized by Fas MAGs or by glycolysis from glucose glycerol in the cell c Lysophsopholipid Reformed into phospholipids in the cell d Cholesterol either packed into chylomicrons directly or esterified into CEs and then packed into chylomicrons e Short Chain Fatty Acids diffuse freely across the cell then bind to albumin portal circulation to the liver i Important process for infants with milk diet f Chylomicron packed with all products then exits the cell and enters the lymphatic system i Apoprotein B48 is very important in the formation of chylomicrons 6 Chylomicron a One B48 protein per one chylomicron molecule b Phospholipid outer layer water loving so that chylomicron can travel through water containing blood c Core of chylomicron is made of triglycerides and cholesterol esters 7 Therapeutic Inhibition of Fat Absorption a Olestra sucrose polyester doesn t offer any calories because cannot be broken down in the body buildup of fats in the colon diarrhea b Orlistat lipase inhibitor inhibits pancreatic lipase so fats will not be broken down into monoglycerides c Decreased fat absorption decreased absorption of fat soluble vitamins
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