Function of secretin is?
Ans. D Bicarbonate secretion from pancreasRef: Quantitative Human Physiology; An Introduction, pg. 711-712Important differences between GIT hormones (Gastrin, CCK, Secretin, GIP) GastrinCCKSecretinGIPSiteMain site: G cells (antrum)I-cells of the proximal two- thirds of small intestineS-cells: Upper small intestineK-cells: Proximal intestinal cryptsActionsMajor:* Stimulate acid and pepsin secretion* Stimulate gastric motility* Act as growth factor to stimulate mucosal proliferationMajor:* Stimulate pancreatic acinar cell enzyme secretion* Stimulate GB contraction* Relaxes sphincter of oddi* Inhibits gastric acid secretion and gastric emptying* Pyloric sphincter contraction* Major: Secretion of HCO3 from biliary and pancreatic ductular cell and Brunner gland.* Inhibit gastric acid secretion* Stimulate pyloric sphincter* Increases bile flow* Augments the action of CCKMajor: Stimulate insulin release from pancreasMajor stimulusPeptides (most potent)Distension of stomach CalciumGRP (gastrin releasing peptides)Peptides (most potent)Fatty acid (BUT NOT TG)Acid (most potent)Digestive proteinGlucose, fat and amino acid
Relax pyloric sphincter
Increase gastric acid secretion
Increase gastric motility
Bicarbonate secretion from pancreas
G.I.T.