BIOS 4500 Lecture Notes - Lecture 23: Gastrin-Releasing Peptide, Gastric Acid, Vagus Nerve
18 Nov 2016
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Document Summary
Rise w/ fasting prior to the meal and decrease following the meal. Bulimics have a blunted release of cck post meals. Endocrine cells dispersed individually throughout the epithelium *aid in digestion. Found in the stomach, and small and large intestines. Most are polypeptides, except ach (from the vagus nerve) and histamine. Grouped into families: gastrin/cck family- have similar prohormones and also active forms, secretin/glucagon family. Control of gastric acid secretion: cephalic phase. Stimuli- sight, smell, taste, or thoughts of food-> central nervous system. Function- prepare the stomach for the arrival of food. Neural mechanism via preganglionic fibers in the vagus nerve and synapses in the submucosal plexus. Homogenizes and acidifies chyme, and initiates digestion of proteins by pepsin. Actions- increased acid and pepsinogen production, and increased motility and. Intestinal phase- functions in controlling the rate of chyme entry into the duodenum.
