PYSO 001 Lecture Notes - Lecture 3: Gastric Inhibitory Polypeptide, Peptic Ulcer, Gastric Acid
12 May 2020
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Document Summary
Peptic ulcers: erosions of mucous membranes of stomach or duodenum due to hcl damage can leak into underlying tissues and cause inflammation and damage histamine release causes further damage. Zollinger-ellison syndrome ulcers of duodenum by excessive gastric acid secretion due to elevated gastrin levels (duodenum normally protected by alkaline pancreatic juice) Gastric ulcer helicobacter pylori (bacteria) infection results in ulcers in stomach and duodenum. Treated with proton pump inhibitors (e. g. prilosec) and antibiotics. Extrinsic control by hormones and autonomic nerves coordinate motility & secretions: Presence of food in stomach simulates secretion of hcl and pepsinogen, etc. Three phases of extrinsic control: cephalic phase: sensory input to brain stimulates gastric secretion via vagus nerve in anticipation of food reaching stomach. Step 1: sight/smell/taste of food causes brain to stimulate vagus (parasympathetic) nerve. Located between pyloric sphincter of stomach and ileocecal valve opening into large intestine. Small diameter but longest part of gi tract (~3 m)
