NFS 243 Lecture Notes - Lecture 3: Lingual Lipase, Gastric Pits, Parietal Cell
22 Jan 2020
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The esophageal sphincter relaxes to open esophagus for bolus. Larynx moves up, inducing epiglottis to shift over the glottis. Lower esophageal sphincter regulates the flow of food from the esophagus into the stomach. Pyloric sphincter regulates the flow of chyme from the stomach into the duodenum. Rugae are small folds in stomach lining that allow for expansion. The entrance to gastric pits contain cells that produce gastric juice. Neck cells surface of gastric pit, produce alkaline mucus for gastric mucosal barrier. Chief cells produce enzymes needed for protein and fat digestion. Parietal cells produce hci and intrinsic factor (for absorption of vitamin b12) G-cells produce gastrin, which stimulates parietal and chief cells. Gastric juice is acidic: bactericide, denatures protein, releases nutrients from organic complexes. Secreted by chief cells stimulated by acetylcholine acid and/or acid endopeptidase, hydrolyzes interior peptide bonds within proteins. Hydrolyzes fatty acids from glycerol"s third carbon on triacylglycerols. Stimuli: sight, smell, taste, or thought of food.
