36 Questions
What hormone inhibits the production of acid in parietal cells by reducing cAMP concentrations?
Somatostatin
Which cells are the most potent regulators of parietal cell secretions?
ECL cells
What is the primary cause of most ulcers, specifically 90% in the duodenum and 70% in the stomach?
Helicobacter pylori infection
Which of the following drugs inhibits the production of acid by parietal cells?
Omeprazole
Pepsinogen, released from chief cells, requires what condition to be converted into the active enzyme pepsin?
Low pH
Which hormone, when acting together with histamine and gastrin, leads to increased acid releasing rate in parietal cells?
Acetylcholine
What stimulates the release of acetylcholine to activate parietal cells in the stomach?
Distension of the stomach
Which hormone stimulates the parietal cells to produce hydrochloric acid in the stomach?
Gastrin
What is the role of G cells in the gastric phase of digestion?
Release gastrin in response to distension
How is salivary secretion regulated?
By release of acetylcholine
Which cells are stimulated by gastrin to produce hydrochloric acid in the stomach?
Parietal cells
What is the pancreatic response to the gastric phase similar to?
Cephalic phase
What hormone is released from S cells in response to highly acidic chyme entering the duodenum?
Secretin
Which hormone enhances acid secretion by parietal cells in response to distension of the duodenum?
Enterooxyntin
What hormone is responsible for inhibiting gastrin release by G cells during the intestinal phase?
Secretin
In the intestinal phase, what stimulates the release of gastrin and enterooxyntin from mechanoreceptors in the duodenum?
Duodenal distension
Which cells release secretin in response to excess hydrogen ions in the duodenal lumen?
S cells
What regulates salivary secretions during the intestinal phase?
Autonomic nervous system
Which hormone is responsible for stimulating gastrin release from G cells during the cephalic phase of digestion?
Gastrin-releasing peptide (GRP)
What is the primary function of gastrin during the cephalic phase of digestion?
Stimulate the release of hydrochloric acid (HCl) from parietal cells
What is the primary role of the vagus nerve during the cephalic phase of digestion?
Indirectly stimulate the release of gastrin by releasing acetylcholine onto interneurons
What is the primary purpose of the low-affinity binding of gastrin to the CCK-1/CCK-alpha receptor on pancreatic acinar cells during the cephalic phase?
To confuse the acinar cells into releasing low volume, high protein secretions
Which hormone is primarily responsible for stimulating pancreatic secretions during the cephalic phase of digestion?
The vagus nerve has a weak stimulatory effect, but no single hormone is primarily responsible
What is the primary function of the gastrin released during the cephalic phase of digestion?
Stimulate the release of hydrochloric acid (HCl) from parietal cells
What is the name of the process where bile acids are actively absorbed in the ileum and returned to the liver?
Enterohepatic circulation
Which phase of digestion occurs before the food enters the stomach and involves thinking about food or smelling food?
Cephalic phase
Which hormone is responsible for stimulating chemo- and mechanoreceptors in the mucosa of the duodenum during the intestinal phase of digestion?
Secretin
During which phase does food enter the duodenum and activate chemo- and mechanoreceptors in the mucosa?
Intestinal phase
What is the primary cause of most ulcers, particularly 90% in the duodenum and 70% in the stomach?
Bacterial infection
Which hormone enhances acid secretion by parietal cells in response to distension of the duodenum?
Cholecystokinin
Which hormone is released during the intestinal phase to inhibit gastric acid secretion?
Somatostatin
What is the primary function of secretin during the intestinal phase?
Increase bicarbonate and enzyme secretion from the pancreas
Which hormone is released by I cells in the duodenum in response to dietary fats and proteins?
Cholecystokinin (CCK)
What is the primary function of gastrin during the intestinal phase?
Inhibit gastric acid secretion in the stomach
Which hormone is released by S cells in the duodenum in response to highly acidic chyme?
Secretin
What is the primary function of cholecystokinin (CCK) during the intestinal phase?
Stimulate the release of bile from the gallbladder and pancreatic enzyme secretion
This quiz covers the physiology of gastric acid secretion, including the factors that stimulate acid production in parietal cells and the concept of alkaline tide. Topics include histamine, gastrin, acetylcholine, and somatostatin's roles in regulating gastric acid levels.
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