BIOS 20188 Lecture Notes - Lecture 23: Muscular Layer, Motilin, Enterocyte
3 Apr 2020
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Lecture 7: explain how the surface area of the small intestines can be 600-fold greater than that of a tube of similar dimensions and explain the significance. Have the same 4 layers as the rest of gi system (inner mucosa layer, submucosa, muscularis externa, and serosal layer) The intestines have wavy rings that increase sa 3x. On the surface of these rings there are villi (finger-like projections) that increase sa another 20x. On top of the villi, the epithelial cells have. Increased sa important because it allows for more area for nutrients to be absorbed in the small intestine: draw and diagram of the structural features of a villus and of the small intestine. Peyer"s patches : secrete lysosomes and signal to the immune system against invading bacteria ( defense mechanism ) part of gut associated lmyphoid tissue. Enterocytes: site of digestion (presence of micrvilli) and transporters for absorption. Terminal lacteals : fat transport (part of lymphatic system)
