NUTR 4320 Lecture Notes - Lecture 1: Pancreatic Juice, Lamina Propria, Jejunum
30 Jan 2018
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Document Summary
Small intestine duodenum, ileum and jejunum: main site for nutrient digestion and absorption, surface area 250m2. Intestinal motility = peristalsis: contraction of inner circular and outer longitudinal muscles, acidic chyme from the stomach is neutralized by pancreatic juice, digestion of food pancreatic juice, bile acids. Kerckring folds (gross folds: 8mm projections, lots in the duodenum and fewer in the jejunum. Microvilli found on each cell 1000 microvilli (1micrometer projections) increase sa by another 20-fold. Total = 250m2 aprox 1000-fold increase in sa. Enterocyte or intestinal epithelial cell barrier: single cell barrier, protects the rest of the body from anything in the lumen (external environment, apical and basolateral borders. Mucosa: epithelial cells nutrient absorption and protection, lamina propria mucosal immune cells. Submucosa: connective tissue, lymphatic and blood vessels. Muscularis externa: smooth muscle layer, outer = longitudinal. Microbiota = collection of all the bacteria that reside in an established environment. Microbiome = all the genetic material found within the microbiota bacteria genome.
