PHY 503: DIGESTIVE FUNCTIONS TEST 1 QUESTIONS WITH
ACCURATE SOLUTIONS
What stimulates the parietal cells to secrete HCl? -- Answer ✔✔ gastrin, histamine, or
ACh
How does the tonicity of gastric secretions compare to the tonicity of the plasma? --
Answer ✔✔ they are always isotonic to the plasma, the secretion rate just changes up
the relative concentrations of the ions
What are the three major functions of gastric acid? -- Answer ✔✔ stop bacterial
growth, convert pepsinogen to pepsin, and begin protein digestion
How does vagal stimulation of HCl secretion occur? -- Answer ✔✔ by direct stimulation
of gastric gland parietal cells, or by stimulation of pyloric gland G cells to release gastrin
that stimulates HCl (indirect)
How does atropine affect the secretion of gastric acid? -- Answer ✔✔ it blocks the M3
muscarinic AChR on the parietal cells, but does not block G cell secretion of gastrin
because ACh is not used to stimulate gastrin release, nor does it block ECL cell
secretion of histamine
, What does somatostatin do? -- Answer ✔✔ inhibits acid and gastrin release
What does gastrin-releasing peptide (GRP) do? -- Answer ✔✔ stimulates gastrin release
from G cells
Presence of which nutrients in the stomach can directly stimulate gastrin release? --
Answer ✔✔ small peptides and amino acids
What stimulates somatostatin secretion from D cells? -- Answer ✔✔ acidification of the
antrum of the stomach (pH <3)
What does histamine do in the stomach? -- Answer ✔✔ binds H2 receptors on parietal
cells to stimulate acid secretion
What substances can stimulate histamine release? -- Answer ✔✔ ACh and gastrin
What are the physiological effects of elevated gastrin besides release of acid? -- Answer
✔✔ increase ECL cell proliferation and histamine release
What is a possible consequence of long-term therapy to reduce gastric acid secretion? --
Answer ✔✔ hypergastrinemia; gastrin is normally inhibited by the presence of antral
gastrin, so when acid secretion is continually suppressed, the serum gastrin will be
chronically high since the feedback mechanism is not being properly engaged
ACCURATE SOLUTIONS
What stimulates the parietal cells to secrete HCl? -- Answer ✔✔ gastrin, histamine, or
ACh
How does the tonicity of gastric secretions compare to the tonicity of the plasma? --
Answer ✔✔ they are always isotonic to the plasma, the secretion rate just changes up
the relative concentrations of the ions
What are the three major functions of gastric acid? -- Answer ✔✔ stop bacterial
growth, convert pepsinogen to pepsin, and begin protein digestion
How does vagal stimulation of HCl secretion occur? -- Answer ✔✔ by direct stimulation
of gastric gland parietal cells, or by stimulation of pyloric gland G cells to release gastrin
that stimulates HCl (indirect)
How does atropine affect the secretion of gastric acid? -- Answer ✔✔ it blocks the M3
muscarinic AChR on the parietal cells, but does not block G cell secretion of gastrin
because ACh is not used to stimulate gastrin release, nor does it block ECL cell
secretion of histamine
, What does somatostatin do? -- Answer ✔✔ inhibits acid and gastrin release
What does gastrin-releasing peptide (GRP) do? -- Answer ✔✔ stimulates gastrin release
from G cells
Presence of which nutrients in the stomach can directly stimulate gastrin release? --
Answer ✔✔ small peptides and amino acids
What stimulates somatostatin secretion from D cells? -- Answer ✔✔ acidification of the
antrum of the stomach (pH <3)
What does histamine do in the stomach? -- Answer ✔✔ binds H2 receptors on parietal
cells to stimulate acid secretion
What substances can stimulate histamine release? -- Answer ✔✔ ACh and gastrin
What are the physiological effects of elevated gastrin besides release of acid? -- Answer
✔✔ increase ECL cell proliferation and histamine release
What is a possible consequence of long-term therapy to reduce gastric acid secretion? --
Answer ✔✔ hypergastrinemia; gastrin is normally inhibited by the presence of antral
gastrin, so when acid secretion is continually suppressed, the serum gastrin will be
chronically high since the feedback mechanism is not being properly engaged
