BIOL 1080 Lecture Notes - Lecture 14: Antibody, Gastrointestinal Tract, Microvillus
16 Nov 2016
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Document Summary
Gi tract: vast surface area of the body that is exposed to the external environment. Mechanisms in place when a toxic/infectious agent is found: 28 ft. long, villi and microvilli increase surface area. Takes 30-80 hours to completely digest 5-8 hours in the stomach/small intestine, rest of time is in the colon. Specialized t cells located in the intestinal mucosa. Four basic processes: motility: peristalsis muscle contractions that push food through, digestion, absorption: absorbs water and nutrients, secretion: saliva, mucous, antibodies, digestive enzymes, bile, and bicarbonate. Chemical and mechanical digestion occurs in the mouth (chewing/mastication). Saliva secretion is stimulated by sns and pns. Provides enzymes: begins digestion of lipids but not proteins. Enzymes released in an inactive form by the pancreas, activated by trypsin. Main enzymes: lipase (fat), chymotrypsinogen and (pro)carboxypeptidase (protein), and amylase (carbohydrate) Breaks down fat and allows it to dissolve in water.
