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GIT hormones

GIT hormones. GIT hormones are CCK Secretin VIP Somatostatin Motilin Glucagon Entero-glucagon Neurotensin

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GIT hormones

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  1. GIT hormones

  2. GIT hormones are CCK Secretin VIP Somatostatin Motilin Glucagon Entero-glucagon Neurotensin GRP Villikinin Gastrin

  3. Gastrin 1-Site of release: G- cells in the antral part of gastric mucosa and duodenal mucosa

  4. Gastrin 34 • 34 amino acid • Big gastrin • Secrete during the interdigestive period (between meals) • Secreted at low basal levels Types

  5. Stimulus for release: • gastric distension • chemical factors (secretagogues) e.g. amino acid , coffee, alcohol, vegetables. • vagal stimulation (bombesin)

  6. Gastrin Actions: Stomach:++secretions (HCL) ++ pyloric pump trophic factor to the mucosa Small intestine: ++ motility Pancreas: ++secretions (enzymes)

  7. Cholecystokinin (pancreozymin) Site of release: Mucosa of the upper small intestine (jejunum) • Stimulus: • digestive products of fats and proteins (+ve feedback) • less by acids

  8. synthesized as a pre-prohormone It has 2 types of receptors: 1)CCK A in the pancreatic acinar cell 2)CCK B in brain and stomach

  9. Cholecystokinin (pancreozymin) 3- Actions: Pancreas:*++secretions ( rich in enzymes by action on pancreatic acini ) * augment secretin * stimulates glucagon secretion Stimulate pancreatic growth Gall bladder:++ evacuation (cholagogue) Small intestine:++secretions & motility Stomach: -- secretions (HCL) & motility

  10. Secretin Site of release: Mucosa of the upper small intestine as prosecretin and activated by acid into secretin • Stimulus: • acid chyme (-ve feedback)

  11. Secretin Actions: Pancreas:* ++secretions (copious and very alkaline by action on pancreatic ducts) *augment CCK Biliary:++bile rich in H2O+HCO3(choleretic Stomach: -- secretions & motility Small intestine: ++ secretions but -- motility

  12. Vaso-active intestinal peptide (VIP) Site of release: Glands and neurons throughout the intestine • Stimulus: • neural stimulation • distension • Acid chyme

  13. Vaso-active intestinal peptide (VIP) Actions: Pancreas:* ++secretions (copious and alkaline by action on pancreatic ducts) Stomach: -- secretions & relax smooth muscles &stimulating pepsinogen secretion by chief cells Small intestine:++secretions but relax smooth muscles Blood vessels:vasodilatation

  14. Somatostatin Growth Hormone Inhibiting Hormone (GHIH) or Somatotropin Release-Inhibiting Factor Site of release: D- cells in pancreas , GIT mucosa and hypothalamus • Stimulus: • according to site of release

  15. Somatostatin _ Actions: Stomach: -- secretions & motility Small intestine: -- secretions & motility Pancreas: -- secretions Gall bladder: -- evacuation

  16. Motilin Site of release: M cells in small intestine(duodenum and jejunum) Stimulus Unknown, although some studies suggest that an alkaline pH in the duodenum stimulates its release Actions: 1-increases the migratory motor complex

  17. villikinin Local hormone released by intestinal mucosa stimulus: digestive products of food. Action: it stimulates movements of villi and help absorption.

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