Class N o t e s Se p t e mbe r 13 2 013 Nutrition Concepts September 13 2013 Digestion and Absorption Digestion Review Saliva helps dissolve food Only particles in solution Portion of food after chewed bolus What do we share with the digestion and absorption pharynx Food through esophagus through diaphragm Epiglottis stops food from going down air pipe Air pipe trachea After diaphragm Esophageal sphincter which prevent re ux Stomach muscular elastic water enzymes and hydrochloric acid with PH of 2 super acidic Salivary enzymes work in that acidity No What digestion occurs in the stomach as a result of hydrochloric acid protein dissolve What protects the stomach Mucus secreted by the cells of the stomach s wall pyloric sphincter after stomach Major site of digestion small intestine ileum duodenum jejunum Pancreas does what secrete insulin glucose homeostasis manufactures digestive enzymes and secretes to the duodenum through pancreatic duct releases bicarbonate to neutralize acid chyme that enters the small intestine Hydrochloric acid from stomach is neutralized by bicarbonate in the pancreas enzymes ace Gastric lipase fats from the stomach Hydrolysis addition of water to break down into smaller pieces Liver digestion manufactures bio salts which are emulsi ers for fat Bring fat into suspension into the water so the enzymes can break them down Gall bladder removed yes digests fat Bio salts come from the liver so can be directly delivered But can t store them anymore Fat malabsorption leads to diarrhea Prevents back ow Appendix Houses bacteria and lymph cells plays a big part in our immune system Large intestine lower part of the intestine that nishes digestion Absorbs water and minerals passes waste ber bacteria and unabsorbed nutrients alone with water to the rectum Bacterial fermentation Absorption Date Se p t 13 2 013 Class N ut r it io n Co n ce p t s Page On e Small Intestine ten feet long majority of absorption surface area simple diffusion high concentration to low concentration some nutrients such facilitated diffusion some nutrients such as the water soluble vitamins are absorption techniques as water and small lipids cross into intestinal cells freely absorbed by facilitated diffusion They need a speci c carrier to transport them from one side of the cell membrane to the other Alternatively facilitated diffusion may occur when the carrier changes the cell membrane in such a away that the nutrients can pass through ACTIVE TRANSPORT requires energy Small intestine the folds increase surface area Villi each covered with microvilli Crypts lie in between the microvilli Artery bringing nutrients Veins taking away Depends on the size of the nutrient what happens to it Lymph itself uid similar to blood but doesn t have platelets or red blood cells Fat soluble vitamins A D E K Lymphatic System bypass liver and enter bloodstream closer to the heart The Vascular System Blood Arteries take blood from the heart Veins takes blood to the heart Capillaries they take oxygens to the cells and from intestines pick up nutrients Heart to arteries to capillaries to veins back to the heart blood ow Goes through Hepatic Portal Vein what happens in the liver ltration detoxi cation because it goes back to the heart Page 2
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