HORMONES OF GIT Slidelearn Team

HORMONES OF GIT Following are the hormones that control the various functions of GIT. These are released from specific site and in response to specific substances Gastrin Cholecystokinin Secretin Gastric inhibitory peptide Motilin

G ASTRIN G cells of the pyloric antrum and duodenum Stimulants for release : 1. Intestinal distention 2. Vagal stimulation 3. Products of protein digestion Effects: 1. Gastric acid secretion 2. Growth of gastric mucosa

C HOLECYSTOKININ Site of secretion: I cells of duodenum and jejunum Stimulants for secretion: Free fatty acids (mainly) Peptides and amino acids (partly) Vagal stimulation Actions i. Emptying of gall bladder - Contraction of gall bladder - Relaxation of sphincter of Oddi ii. Decreased gastric motor activity

G ASTRIC INHIBITORY PEPTIDE Site of release: K cells of duodenal and jejunal mucosa Stimulants for secretion: Fats, amino acids Glucose Effects (i)Release of insulin (ii)Mildly slows down gastric emptying

M OTILIN Site of release: Enterochromaffin cells of duodenal mucosa Stimulants for release: HCl (decreased pH), fats in duodenal chyme Actions Increased motility of fundus and pyloric antrum

S ECRETIN Site of release: second part of duodenum Stimulants for release Acidic chyme from stomach Actions Contain HCO3 in high amount that Neutralizes the acidic pH of chyme Give optimum pH in intestine for proper functioning of various enzymes