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17 Cards in this Set
- Front
- Back
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What are the primary functions of the stomach?
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STORAGE--80% of food is stored in the proximal stomach
Digestion with acid and pepsin Bactericidal barrier Exocrine, paracrine, and endocrine secretions |
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What cells secrete acid? Where are they contained?
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Parietal cells--gastric pits
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What is the key transporter in acid secretion in the stomach? Is it active or passive transport?
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H/K ATPase--it is electroneutral and is active because it is pushing hydrogen ions against their gradient
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What do parietal cells contain that allow them to secrete bicarb.? What facilitates this?
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Full of carbonic anhydrase--chloride bicarb. exchanger at the base of the membrane
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What is the key player in acid secretion that is inhibited by drugs?
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The H/K ATPase
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What three agents are important in the regulation of acid?
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Gastrin--binds CCK-B receptor at the basolateral membrane
ACh--coming from vagus/enteric nervous system and binding muscularis receptor Histamine working on H2 receptors coupled to PKA |
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What chemical inhibits G cells? When is it secreted?
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Somatostatin--when the pH is <3
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What inhibits gastrin secretion?
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Low acid, contents in the duodenum, fatty acids in the duodenum/jejunum, somatostatin
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What are the layers of mucous that protect the stomach epithelium?
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The loosely adherent mucous layer and firmly adherent mucus layer
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What will happen to the mucus layer when you inhibit cyclooxygenase?
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It will decrease because prostaglandins stimulate mucus secretion
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What is the first quantitatively important enzyme that the food encounters?
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Pepsinogen
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What secretes pepsinogen?
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Secreted by chief cells(don't worry about Group 1 vs. group 2)
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What cleaves pepsinogen?
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Acid and pepsin
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What stimulates pepsinogen release?
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Vagal efferents and the enteric nervous system--Secretin secreted from the duodenum
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What secretes intrinsic factor? What stimulates its release?
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Parietal cells--anything that stimulates acid secretion also stimulates intrinsic factor release
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What is intrinsic factor essential for? Deficiency causes?
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Absorption of Vit B12--pernicious anemia
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How is Vit B12 absorbed?
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R proteins secreted by the salivary glands bind the B12 and some other stuff happens
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