Gastrointestinal Hormones Flashcards
What is gastrin released by?
G cells in antrum of the stomach
What 3 things is gastrin secretion stimulated by?
-Distension of stomach
-Vagus nerves (mediated by gastrin-releasing peptide)
-Luminal peptides/amino acids
What 2 things is gastrin secretion inhibited by?
-Low antral pH
-Somatostatin
What 4 actions is gastrin responsible for?
-Increases acid secretion by gastric parietal cells
-Pepsinogen and IF secretion
-Increases gastric motility
-Stimulates parietal cell maturation
What is CCK secreted by?
I cells in upper small intestine
What 2 things is CCK secretion stimulated by?
Partially digested proteins and triglycerides
What 5 actions is CCK responsible for?
-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 secretin secreted by?
S cells in upper small intestine
What 2 things is secretin secretion stimulated by?
-Acidic chyme
-Fatty acids
What 3 actions is secretin responsible for?
-Increases secretion of bicarbonate-rich fluid from pancreas and hepatic duct cells
-Decreases gastric acid secretion
-Trophic effect on pancreatic acinar cells
What is VIP?
vasoactive intestinal peptide
What 2 things is VIP secreted by?
Small intestine and pancreas
What thing is VIP secretion stimulated by
Neural
What action is VIP responsible for?
Inhibits acid secretion
What 2 things is somatostatin secreted by?
D cells in the pancreas & stomach
