BIO 203 Lecture Notes - Lecture 1: Myenteric Plexus, Motility, Norepinephrine
10 Aug 2016
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Bases are absorbed by active transport and monosaccharides absorbed by facilitated diffusion and secondary active transport. Fat soluble vitamins (a, d, e and k) are absorbed in small intestine along with fats. Water soluble vitamins (c and most b) are absorbed by mediated transport. Exception would be b12 also known as cobalamin. Intestinal transporter for b12 is found in ileum and can be recognized when vitamin is complexed with intrinsic factor secreted by gastric parietal cells. Decrease in body concentrations of mineral leads to enhanced uptake at intestine. Heme iron (meat) absorbed by an apical transporter on the enterocyte. Ionized iron is actively absorbed by apical cotransport with h on protein called divalent metal transporter 1 (dmt1) Inside the cell, enzymes convert heme iron to fe and both pools of ionized iron leave the cell on a transporter called ferroportin. Iron uptake by body is regulated by a peptide hormone called hepcidin which binds to ferroportin.
