Lecture 18 Outline of Last Lecture I. Salivary GlandsII. TeethIII. Pharynx/EsophagusIV. Digestive Processes: Mouth – EsophagusV. StomachVI. Stomach MucosaVII. Gastric Secretion RegulationVIII. Regulation of HCl SecretionIX. Gastric MotilityX. Gastric EmptyingXI. Small IntestineXII. Liver LobulesXIII. Accessories to Small IntestineXIV. BileXV. Role of the PancreasXVI. Pancreatic RegulationXVII. Digestion: Small IntestineXVIII. Motility: Small IntestineXIX. Large IntestineXX. Large Intestine: Microscopic AnatomyXXI. Motility & DefecationXXII. CancerXXIII. Malabsorption of NutrientsXXIV. UlcersXXV. Developmental ConsiderationsOutline of Current Lecture I. Nutrition & Metabolisma. Major NutrientsII. Digestion of NutrientsIII. Lipid Metabolisma. Lipid CatabolismCurrent LectureNutrition & Metabolism- Major Nutrientso Carbohydrates BIOL 320 1st Edition Complex = whole grains & veggies Simple = monosaccharaides & disaccharides (fruits, honey, milk) Refined = candy…EMPTY calories Glucose = molecule used by cells to make ATPo Lipids Most abundant: triglycerides, found in both animal & plant foods Essential fatty acids = linoleic & linolenic (in most veggies) Dietary fat functions = help absorb vitamins; energy for cells; myelin sheaths; cell membranes; protective cushioning; insulation & fuel Prostaglandins (from linoleic acid via arachidonic acid) = helps smooth muscle contraction, blood pressure regulation, & inflammation Dietary requirements (higher for infants/kids) = 30% total caloric in with saturated fat max 10% & cholesterol less than 200mg Cholesterol: stabilizes membrane, precursor of bile salts & steroid hormoneso Proteins Complete (eggs, milk, meats) = meat amino acid requirements for tissue maintain & growth Incomplete (legumes, nuts, seeds, grains, & vegetables) Use of amino acid depends on:- All-or-none rule (must be present at same time- Adequacy of caloric intake- Nitrogen balance- Hormonal control (anabolics)o Vitamins: organic compounds needed in small amounts (not for energy or building blocks) Function: most act as coenzymes Synthesized in body = D (skin, K (intestinal bacteria), A Essential vitamins = the rest Water soluble vitamins (B,C): absorbed in GI tract Fat soluble (A,D,E,K) bind to ingested lipids & absorbed with their digestion products Vitamins A,C,& E also act in antioxidant cascadeo Minerals: inorganic chemical compounds found in nature, salts Function: minerals work with nutrients to ensure proper body functioning Moderate amounts required = Ca, P, K, S, Na, Cl, & Mg Trace amounts required = many! Ca, P, and Mg salts harden bone Na & Cl help maintain normal osmolarity, water balance, essential in nerve and muscle function Uptake & excretion must be balancedDigestion of NutrientsLipid Metabolismo Catabolism of fats involves two separate pathwayso Glycerol pathway (glyceraldehyde phosphate-AcCoA)o Fatty acids pathway (beta oxidation, cleaving two carbons and reduction of two coenzymes)oo Lipid Catabolismo Glycerol Glyceraldehyde-phosphate Glucose (via liver) 18 ATPo Fatty acids Acetyl CoA (Beta Oxidation) 12 ATP per pair of carbons (12 x 9 = 108 ATP) Every pair released…5 more ATP (5 x 8 = 40 additional ATP) Cost 1 ATP Total for 18 carbon fatty acid = 147
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