PHYL2001 Lecture Notes - Lecture 18: Stomach, Pepsin, Gastrin
Document Summary
In stomach have cells involved in producing hcl and pepsinogen broken down by acid to pepsin. If lose histamine, we lose pepsinogen and hcl to a greater extent than losing gastrin. In close proximity is antral somatostatin cell: detection system for dropping ph, ensures acidic secretion not too high. Get acid and pepsinogen secretion: ph drops, overreaches mark gets too low, antra somatostatin cells binds to g cells, causes it to start making and secreting less gastrin to bring ph up again. Synergistic, drop one of 3 cell activators, decrease synthesis of acid at parietal cell level. Produce: mucosal barrier, high levels bicarbonate. In stomach have acid and pepsinogen secretion that gets rid of big lumps of protein. Mucous surface cells secrete bicarbonate to stomach. Mucous create barrier between surface of stomach: secrete high levels of bicarbonate and stops stomach being digested from wn acids and proteases, viscous gel like lining, slows down diffusion of stomach content.
