Term
| What do cardiac glands secrete? |
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Definition
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Term
| 3 regions of the carnivore stomach |
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Definition
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Term
| Where are parietal cells found in the stomach |
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Definition
| fundic region & body of stomach - gastric pits |
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Term
| Main cell types found in the fundic region (5) |
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Definition
Mucous cells
Parietal ccells
Chief cells
Enteroendocrine Cells
Mast Cells |
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Term
| What do parietal cells secrete |
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Definition
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Term
| What do chief cells secrete |
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Definition
| zymogens (aka pepsinogens) |
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Term
| What is the importance of intrinsic factor? |
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Definition
| required for absorption of B12 in ileum |
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Term
| What two hormones inhibit parietal cell secretion? |
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Definition
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Term
| How can you inhibit acid secretion to promote healing of gastric ulcers |
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Definition
Parietal cells make acid by splitting hydrogen from H2O, and H+ is then transported into the lumen of the gland
-inhibiting synthesis or transport of H+ inhibits acid secretion into stomach
-carbonic annhydrase inhibitors prevent splitting of water, (carb ann catalyzes the splitting reaction)
OR
-proton pump inhibitors to prevent H+ from being exported into lumen, will promote carbonic annhydrase to carry out the reverse reaction and produce H2O |
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Term
| What is required for zymogens (pepsinogens) to become active? |
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Definition
| cleavage by HCl to produce active pepsin |
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Term
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Definition
gastric enzyme of ruminants, cleaved from chymosinogen
-found in abomasum
-curdles milk, slowing its movement from stomach to intestine (in young animals) |
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Term
| ____ cells secrete histamine which stimulates parietal cells to secrete ____ |
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Definition
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Term
True or False
G-cells secret gastrin into the stomach |
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Definition
false
secrete gastrin into the blood, in response to peptides/AAs/Ca in stomach |
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Term
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Definition
promotes HCl secretion
promotes histamine secretion |
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Term
| How is HCl secretion promoted? (2 phases) |
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Definition
Cephalic phase
-PSNS promotes vagus to release AcH in anticipation of food
-ACh stimulates muscarinic receptors on parietal cells (secretes HCl) and g cells (secrete gastrin which promotes HCl secretion)
Gastric Phase
-chemoreceptors & stretch receptors promote ENS to release ACh
-more ACh stimulation of G cells & parietal cells
-further increase of HCl secretion
-food in stomach also raises pH which promotes more HCl secretion |
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Term
| The main goal of the gastric phase is to... |
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Definition
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Term
| What does histamine do in the stomach? |
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Definition
| binds to H2 receptors on parietal cells to promote HCl release |
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Term
| How is HCl secretion inhibited? |
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Definition
if pH of chyme drops too low, gastrin production is inhibited, parietal cell secretion of HCl reduced
-chyme in duodenum triggers somatostatin (inhibits HCl secretion)
-drop in pH in duodenum triggers secretin release, which promotes secretion of bicarbonate into SI
-chyme presence also triggers secretion of CCK into bloodstream, stimulating release of digestive enzymes into duodenum |
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Term
| 4 methods of treating ulcers in order of increasing importance |
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Definition
1. Antacids to temporarily increase pH
2. Surface protectants to coat ulcer
3. H2 receptor antagonists to prevent hist. from binding to parietal cells
4. Proton pump inhibitors to prevent H+ from being pumped into lumen of cells |
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