GI physiology resources Flashcards
what is the source of gastrin?
G cells in antrum of the stomach
what stimulates gastrin release?
Distension of stomach, vagus nerves (mediated by gastrin-releasing peptide), luminal peptides/amino acids
what inhibits gastrin release?
Inhibited by: low antral pH, somatostatin
what are the actions of gastrin?
Increases acid secretion by gastric parietal cells, pepsinogen and IF secretion, increases gastric motility, stimulates parietal cell maturation
what is the source of CCK?
I cells in upper small intestine
what stimulates CCK?
Partially digested proteins and triglycerides
what is the action of CCK?
Increases secretion of enzyme-rich fluid from pancreas, contraction of gallbladder and relaxation of sphincter of Oddi, decreases gastric emptying, trophic effect on pancreatic acinar cells, induces satiety
what is the source of secretin?
S cells in upper small intestine
what stimulates secretin?
Acidic chyme, fatty acids
what are the actions of secretin?
Increases secretion of bicarbonate-rich fluid from pancreas and hepatic duct cells, decreases gastric acid secretion, trophic effect on pancreatic acinar cells
what is the source of VIP?
Small intestine, pancreas
what is the source of VIP
Neural
what is the action of VIP
Stimulates secretion by pancreas and intestines, inhibits acid secretion
what is the source of somatostatin?
D cells in the pancreas & stomach
what is the stimulus for somatostatin?
Fat, bile salts and glucose in the intestinal lumen
