Hormones of Digestion

Question 1

Gastrin

Answer 1

Source - G cells in antrum of the stomach
Stimulus - Distension of stomach, extrinsic nerves
Inhibited by: low antral pH, somatostatin
Actions - Increase HCL, pepsinogen and IF secretion, increases gastric motility, trophic effect on gastric mucosa

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 and pepsinogen secretion

Question 5

Somatostatin

Answer 5

Source - D cells in the pancreas and 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