<prompt> Function of secretin is?Relax pyloric sphincterIncrease gastric acid secretionIncrease gastric motilityBicarbonate secretion from pancreas  <response>: 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 antrumI-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 potentDistension of stomach CalciumGRP gastrin releasing peptidesPeptides most potentFatty acid BUT NOT TGAcid most potentDigestive proteinGlucose, fat and amino acid 