NUSCTX 103 Lecture Notes - Lecture 2: Ileocecal Valve, Pylorus, Gastrointestinal Tract
3 Dec 2020
School
Department
Course
Professor
Document Summary
Small intestine - intestinal wall: mucosa absorptive/secretory layer, submucosa vascular connective tissue, muscularis peristaltic movement, serosa protective layer. Amplification of mucosal surface for maximal absorption: enlarge surface area!!!! 600 fold amplification: villi, epithelial cells, microvilli (brush border) What is absorbed where in the small intestine: duodenum and jejunum (upper 40% of length, carbs, lipids, amino acids, calcium, iron. Ileum (lower 60% of length: bile salts, vitamin b12, h2o, electrolytes. Increase gastric activity increase ileal activity increase flow: want everything to flow fast if you"ve got a lot of food. Ileogastric reflex: distention of ileum decrease gastric motility, when your food is being piled up, it will signal your stomach to not pump out chyme as fast. Illeal break: nutrients in chyme decrease gastric emptying and intestinal motility, body will signal that you already have a lot of nutrients to slow down a bit. Intestino-intestinal reflex: overextension of any segment relaxes others.
