Gastric Acid Secretion Module (Quiz) Flashcards
gastric acid is the form of
- hydrochloric acid
gastric acids secreted from _______ cells within the ______ glands of the _______.
- parietal cells
- oxyntic glands
- stomach
what happens to the parietal cell as it goes from resting state to secreting state
- changes its configuration
parietal cell at rest
- apical H+/K+ ATPase sequestered in tubulovesicles inside parietal cell
what happens to the tubulovesicles when the parietal cell is stimulated to secrete acid
- fuse with intracellular canaliculi
what happens when the tubulovesicles fuse with the intracellular canaliculi
- bulk of microvilli increases dramatically to accommodate proton pumps
why do the bulk of microvilli increase dramatically to accommodate proton pumps
- increases surface area of parietal cell that faces lumen of stomach
acid in the stomach is generated through activity of
what is produced
- carbonic anhydrase
- protons and bicarbonate
exchange of the apical H/K-ATPase made possible by basolateral _______.
The secretion of ______ into the lumen is accompanied by the release of _____ into the bloodstream via the ______ antiporter
- Na/K ATPase
- protons
- bicarbonate
- Cl/HCO3
result of flux of bicarb ions into the blood
name for this
- increase pH of gastric venous blood
- alkaline tide
principal stimuli of acid secretion from parietal cells
- acetylcholine
- histamine
- gastrin
_______ and ______ promote secretion by elevating cytosolic free calcium concentration
- gastrin
- acetylcholine
_______ promotes acid secretion through intracellular cAMP
- histamine
the ______ aspect of the parietal cell membrane holds receptors for agonists for acid secretion
- basolateral
acetylcholine released by nerve endings from the _______ nerve activates the _______ receptor
- vagus nerve
- M3 muscarinic receptor
histamine is released from the ________ and acts in a _______ fashion to stimulate ______ receptor
- ECL cells
- paracrine fashion
- H2 histamine receptor
gastrin is produced by _________ and travels via the bloodstream in an ________ fashion to agonize the ________ receptor on the _______ cell
- antral G cells
- endocrine
- gastrin receptor
- parietal cell
another name for gastrin receptor
- CCK-B receptor
both _____ and ______ stimulate ECL cells to _________
- gastrin and acetylcholine
- produce histamine
another name for GRP
released from
- bombesin
- enteric nerves
additional stimuli for gastrin secretion
- peptides and amino acids (protein breakdown products)
- gastric distention
phases of gastric acid secretion
- cephalic phase
- gastric phase
- intestinal phase
gastric juice pH before cephalic phase (during interdigestive phase)
<2
the cephalic phase is characterized by
- vagal stimulation of acid production
vagus nerve in cephalic phase stimulated by
- smell, taste
- chewing
- swallowing
- hypoglycemia
- conditioned reflexes
gastric phase accounts for _____ of acid production in response to a meal
- 50%
gastrin release inhibited at a pH ____ and eliminated at a pH _____
<3
<2
distention of stomach stimulates ______ to activate ______ pathways to increase acid production
- mechanoreceptors
- 2 neural reflex pathways
which are the short neural reflex pathways
- pyloro-pyloric
pyloro-pyloric located where
- wall of stomach
pyloro-pyloric involve _______ neurons
- single neurons or intermediary neurons
which are the long reflex pathways
- vagovagal reflex
afferent signals in vagovagal reflex carried from _______ to _________
efferent signals carried from ________ to _______ to ________
- from stomach to vagal nucleus
- carried from vagal nucleus back to stomach to increase acid production
what happens during the intestinal phase of gastric acid production
- protein breakdown products stimulate duodenal G cells to produce gastrin
