Gastro Medicine - Gastrointestinal hormones

Question 1

Gastrin?

Answer 1

Source - G cells in antrum of the stomach

Stimulus - Distension of stomach, vagus nerves (mediated by gastrin-releasing peptide), luminal peptides/amino acids
Inhibited by: low antral pH, somatostatin

Actions - Increase HCL, pepsinogen and IF secretion, increases gastric motility, stimulates parietal cell maturation

Question 2

CCK?

Answer 2

Source: I cells in upper small intestine

Stimulus: Partially digested proteins and triglycerides

Actions: 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

Question 3

Secretin?

Answer 3

Source: S cells in upper small intestine

Stimulus: Acidic chyme, fatty acids

Actions: Increases secretion of bicarbonate-rich fluid from pancreas and hepatic duct cells, decreases gastric acid secretion, trophic effect on pancreatic acinar cells

Question 4

VIP?

Answer 4

Source: Small intestine, pancreas

Stimulus: Neural

Actions: Stimulates secretion by pancreas and intestines, inhibits acid secretion

Question 5

Somatostatin?

Answer 5

Source: D cells in the pancreas & stomach

Stimulus: Fat, bile salts and glucose in the intestinal lumen

Actions: Decreases acid and pepsin secretion, decreases gastrin secretion, decreases pancreatic enzyme secretion, decreases insulin and glucagon secretion
inhibits trophic effects of gastrin, stimulates gastric mucous production