PHSI 208 Lecture Notes - Lecture 54: Taenia Coli, Trpv6, Paracellular Transport
Document Summary
Protein digestion primarily results in free amino acids, dipeptide and tripeptides. Most single aa"s on na+ cotransporters (apical) and na+ exchangers (basolateral) Di and tripeptides on oligopeptide transporter (h+ cotransporter) Most ligos digested to single aa"s in cell (peptidases) and exit via na-aa exchanger. Peptides larger that 3 aa"s transported via transcytosis after binding to a receptor on the luminal surface rare in adults! Small peptides could potentially act as antigens stimulating antibody production causing an allergic reaction: peptide absorption high when infant (villi are small, may play a role in food intolerances or allergies. Fat soluble vitamins (a, d, e and k) absorbed w/ fats. Water soluble (c and most b) are absorbed by mediated transport: b12 is absorbed in the ileum after forming a complex w/ intrinsic factor released from parietal cells. Mineral absorption is usually by active transport. Most water absorbed in the small intestine.
