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14 Cards in this Set
- Front
- Back
pepsinogen is what HCL for what |
-protein digesting enzyme -dissolving food, partially digesting macromolecules in food, sterilizing food |
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-fundus and body -antrum |
-think layer of smooth muscle, secretes HCL, pepsinogen, mucous -thick layer of smooth muscle, secretes gastrin, pepsinogen, mucous |
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-major exocrine secretions of the stomach -minor endocrine |
- mucous, HCL (hydrolysis of proteins), pepsinogen (digestions of proteins) - gastrin (endocrine: stimulates HCL and stomach motility), intrinsic factor (vitamin b12), histamine (paracrine,stimulates HCL), somatostatin (endocrine, inhibits HCL) |
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gastric gland cells |
- chief cells: pepsinogen, accelerates protein digestion -enteroendocrine cells: gastrin (so only in antrum) also G cell - ECL cells- histamine (more in antrum) - D cells: somatostatin - parietal cells: HCL, has canaliculi |
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acid secretion from the parietal cell requires what |
energy- lots of mitochondria |
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lumen pH vs cytosol |
lumen 1 (more acid in stomach) cytosol 7 |
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5 steps of acidification of stomach lumen |
-K/H ATPase -CA: H2O/CO2 --> H2CO3 --> H+/ HCO3 - - HCO3-/Cl- -K out -Cl out |
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which 4 chemical messengers regulate the insertion of H/K ATPase |
ACh, histamine, somatostatin, gastrin |
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pepsinogen secretion and activation |
- stimulated by ENS - cleaved and activated to pepsin when in acidic pH (stomach) - reversibly deactivates in intestine |
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3 phases or gastric secretion |
- cephalic phase (head, excitatory via vagus) - gastric phase (excitatory, via gastrin) - intestinal phase (inhibitory) |
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-acetylcholine, gastrin, histamine all do what to parietal cell -somatostatin does what to parietal cell -ACh also does what - gastrin does what |
- induces HCL - inhibits HCL - induces HCL by raised the first set, and inhibiting the inhibitor - induces histamine = more HCL |
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once acid secretion is at a high rate... |
- reduced parasympathetic - negative feedback for gastrin - increased somatostatin because: reduced para inhibition of D cell, acid stimulates somatostatin. It then inhibits parietal, ECL, G cell |
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steps of vomiting |
- nausea, salivation, hold breath - glottis closes off trachea - esophagus and its sphincter relax - diaphragm and stomach muscle contract - reverse peristalsis -food moves us |
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ulcers and what is it caused by |
- erosion of GIT mucosa usually in acidic regions - imbalance between protective and aggressive factors, helicobacter pylori, alcohol, smoking, stress, gastrinomas |