This document discusses gastrointestinal hormones and their roles in regulating gastrointestinal secretion and motility. It describes six key GI hormones: gastrin, secretin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), motilin, and peptide YY. For each hormone, it provides information on the site of secretion, primary stimuli for secretion, and general actions in the GI tract. The hormones act in a paracrine or endocrine fashion to regulate processes like gastric acid secretion, pancreatic enzyme secretion, gallbladder contraction, and gastrointestinal motility.

1. GI HORMONES
Dr. Aviral Srivastav

2. • Biologically active polypeptides that are secreted by nerve cells and
gland cells in the mucosa act in a paracrine fashion, but they also
enter the circulation. Measurement of their concentrations inblood
after a meal has shed light on the roles these gastrointestinal
hormones play in the regulation of gastrointestinal secretion and
motility.

3. GI Hormone
• gastrin
• secretin
• CCK
• gastric inhibitory peptide, aka
GIP
• Molitin
• Peptide YY

4. Gastrin
• Site
-G cell in antrum of stomach and
duodenum
• primary stimuli
-Strech,peptide and amino acid ,
vagus (through GRP)
• general action
-↑Gastric H＋
-↑Gastric mixing
-↑lower gi tract motility

5. Motilin
• Motilin is a polypeptide containing 22 amino acid residues that is
secreted by enterochromaffin cells and Mo cells in the stomach,
small intestine, and colon. It acts on G-protein-coupled receptors on
enteric neurons in the duodenum and colon and produces
contraction of smooth musclein the stomach and intestines in the
period between meals.

6. Secretin
• Site - s cell of the duodenum
• primary stimuli -Acid chyme
• general action -increase pancreatic buffer secretion
-decrease gastric H ion
-decrease Gastric emptying

7. CCK
• Site - I cell of the duodenum and jejenum
• primary stimuli -small peptide and amino acid , fats
• general action - increases pancreatic enzyme secretion
-contract gall bladder and relax sphincter of oddi
decrease gastric emptying
-increases lower gi tarct motility
-increases pancreatic buffer secretion

8. GIP
• Site - duodenum and jejenum
• primary stimuli -Fatty acid , glucose and amino acid
• general action -increases gastric H ion secretion
-increases insulin secretion
-inreases phase III contaction of MMC
-decreases gastric emptying

9. Integrated action of GI hormone

11. THANK YOU