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5 Cards in this Set
- Front
- Back
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Name and describe all the different gastric secretions.
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1. HCL - from parietal cells. Important in digestion and breakdown of food. Also provides antimicrobial action!
2. IF - from parietal cells. IF combines with B12/r-protein to make IF/B12/R complex. In the small intestine trypsin will cleave the R protein and will get B12/IF to dimerize. This dimerization protects B12 until it reaches the terminal ileum where it can be absorbed. 3. Pepsinogens, zymogens (inactive form of pepsin activated by acid) Pepsin is a very active protease in this acidic environment.Allows for the beginning of protein digestion in the stomach. (starch and fat begins in the mouth) 4. Gastrin - produced in antral G cells, it circulates in the blood, reaching the parietal cell sin the antrum of the stomach where it stimulates HCL secretion. Stomach strech stimulates gastrin which stimulates HCL secretion. |
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Additional gastric secretions...
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5. Lipase - continues hydrolysis of lipids begun in the saliva, and it works optimally in the acidic stomach.
6. Somatostatins (SS) - decrease HCL secretion. 7. Histamine (Hist) - increase HCL secretion. 8. Mucus - traps HCO3 and protects the body from the acid by lining the stomach. There is a constant regeneration of these cells to keep the lining intact. An ulcer gets through this mucus and attacks the parenchyma (tissue). |
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Cells of the Gastric Mucosa...
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1. Endocrine cells - produce SS and gastrin.
2. Chief cells - produce pepsinogen and lipase. 3. Parietal cells - produce HCL and IF. 4. Regenerative cells 0 migrate up or down to replace cells that have been sloughed off 5. Mucous neck cells - produce mucus and HCO3 and traps it within a couplf of mm above gastric mucosal. |
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Control of gastric secretions...
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Gastric secretion is under intrinsic control. Denervation of the vagus n. does not prohibit acid secretion b.c gastrin in the blood travels through the circulation and effects the parietal cells in the stomach. The vagus n. is not completely useless.. it can enhance HCL secretion.
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What does the esophogus secrete?
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serous and mucus glands in the esophogus lubricate a food bolus with electrolytes and mucin to aid it's propulsion down to the stomach.
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