PHRM 311 Lecture Notes - Lecithin, Ileum, Common Hepatic Duct
Document Summary
Anatomy and physiology of the gi system (part 2) Mechanically breaks down food through contractions in lower 2/3 of the organ. Gastric pacemaker creates regular rate of stomach contraction of about 3 per minute. Controls food delivery to small intestine to meet digestive and absorptive capacity short pyloric sphincter openings adjusted for food (liquids faster than solids) Reservoir for food to slow movement relaxes to increase its volume after food is consumed until the stomach empties (via the vago-vagal reflex) Gastric secretions mucosa (lining cells) secretes mucus and bicarbonate for protection. The stomach is lined with gastric glands that contain 4 types of cells: Parietal cells secrete hcl & intrinsic factor (vit b12) Enteroendocrine cells secret gastrin (stimulates hcl and pepsinogen release) Gastrin hormone released into circulation by g cells when food bolus enters the stomach. Acts on parietal cells (directly, and by increasing histamine release by enterochromaffin like cells) to promote acid production.
