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gastro-intestinal tract of poultry simple stomached

Gastro-intestinal Tract of Poultry (Simple Stomached). Gastro-intestinal Tract of the Horse (Simple Stomached Non-ruminant Herbivore). Gastro-intestinal Tract of the Pig (Simple Stomached). Gastro-intestinal Tract of the Cow (Ruminant). Phases of Digestion - Stomach. Cephalic phase

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gastro-intestinal tract of poultry simple stomached

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    3. Gastro-intestinal Tract of the Horse (Simple Stomached Non-ruminant Herbivore)

    4. Gastro-intestinal Tract of the Pig (Simple Stomached)

    5. Gastro-intestinal Tract of the Cow (Ruminant)

    8. Phases of Digestion - Stomach Cephalic phase – seeing, smelling, anticipating food

    9. Phases of Digestion - Stomach Cephalic phase – seeing, smelling, anticipating food Gastric Phase – meal enters the stomach, distension, mucosal irritation

    10. “Experiments and observations on gastric juice and physiology of digestion” W.W. Beaumont, 1829 ….patient with a gastric fistula, gastric acid follows ingestion of a meal

    11. Late 19 th Century, nervism or exclusive role of nerves in control of digestive secretion… “Lectures on Conditioned Reflexes” Ivan Pavlov, 1926 Nobel Prize, 1904 …. the essential role of the central nervous system and vagal nerves in the stimulation of gastric secretion, sham feeding and ordinary feeding

    12. ….the exploration of new biological agents discharged by particular tissue cells directly into blood, they were called hormones, the name coined by English physiologists William Bayliss (1860-1924) and Ernest Starling (1866-1927) from the University College in London.

    13. First discovery of hormonal control of pancreatic secretion by non-nervous substance, Secretin Bayliss and Starling, 1902. The mechanism of pancreatic secretion. J. Physiology (London) 22:325-330.

    14. The control of gastric secretionGASTRIN J. Edkins, 1906 The chemical mechanisms of gastric secretion. J. Physiology (London) 34:133-144.

    16. Controversy in the halls of science Popielski strongly objected to the hormonal theory, he challenged Edkins' concept according to which the secretion of the stomach juice is stimulated by the "stomach secretion" (gastrin).

    17. …acetycholine and histamine became the focal points as the principal regulators of acid secretion….

    18. The Nobel Prize in Physiology or Medicine 1936 Sir Henry Dale Otto Leowi "for their discoveries relating to chemical transmission of nerve impulses and appreciation for acetylcholine and histamine as physiological regulators"

    19. Parietal Cells The stomach secretes HCl in direct proportion to the number of parietal cells (oxyntic cells) Resulting pH of 0.8 (160 mM) Enzymatically driven – carbonic anhydrase Carbonic anhydrase, H/K ATPase (proton pump) Excessive secretion of acid is a major problem in humans

    21. Intrinsic Factor Intrinsic factor is a glycoprotein secreted by parietal cells (humans) or chief cells (rodents)

    22. Intrinsic Factor Intrinsic factor is a glycoprotein secreted by parietal cells (humans) or chief cells (rodents) Vitamin B12 is digested and released from dietary proteins and rapidly bound to two Vitamin B12 binding proteins.

    23. Intrinsic Factor Intrinsic factor is a glycoprotein secreted by parietal cells (humans) or chief cells (rodents) Vitamin B12 is digested and released from dietary proteins and rapidly bound to two Vitamin B12 binding proteins. The binding proteins are digested within the intestine, releasing Vitamin B12

    24. Intrinsic Factor, cont’d The vitamin becomes bound to intrinsic factor in the intestine and there are receptors for the vitamin-IF complex on mucosal cells.

    25. Intrinsic Factor, cont’d The vitamin becomes bound to intrinsic factor in the intestine and there are receptors for the vitamin-IF complex on mucosal cells. Vitamin B12 is need for erythrocyte maturation and a deficiency leads to anemia.

    26. Intrinsic Factor, cont’d The vitamin becomes bound to intrinsic factor in the intestine and there are receptors for the vitamin-IF complex on mucosal cells. Vitamin B12 is need for erythrocyte maturation and a deficiency leads to anemia. Cobalt is a key co-factor in the activity of this vitamin.

    27. Enterochromaffin-Like Cells Distinctive type of endocrine cell within the mucosa – prevalent in acid secreting regions. ECL cells synthesize and secrete histamine in response to gastrin. Histamine and gastrin become the primary regulators of acid secretion by parietal cells.

    28. Intestinal Feedback Enterogastric reflex - chemical and osmotic irritation of the mucosa sends gastric-inhibitory impulses via the enteric nervous system Enteric hormones – cholecystokinin and secretin are released from cells in the small intestine, suppress gastric activity

    29. Enterochromaffin-Like Cells Distinctive type of endocrine cell within the mucosa – prevalent in acid secreting regions.

    30. Enterochromaffin-Like Cells Distinctive type of endocrine cell within the mucosa – prevalent in acid secreting regions. ECL cells synthesize and secrete histamine in response to gastrin.

    31. Enterochromaffin-Like Cells Distinctive type of endocrine cell within the mucosa – prevalent in acid secreting regions. ECL cells synthesize and secrete histamine in response to gastrin. Histamine and gastrin become the primary regulators of acid secretion by parietal cells.

    32. Komarow, 1938. ..evidence that a histamine free extract was effective in the stimulation of gastric secretion in cats, effect was not influenced by neural blockers

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