Which hormone(s) influences the release of hydrochloric acid from the parietal cells in the stomach
A) renin and cholecystokinin
B) cholecystokinin and secretin
C) gastrin
D) cholecystokinin
E) gastrin and renin
The correct answer and explanation is:
The correct answer is C) gastrin.
Gastrin is a hormone produced by G cells in the stomach lining. It plays a key role in stimulating the parietal cells in the stomach to release hydrochloric acid (HCl), which is essential for the digestion of food. The release of hydrochloric acid helps in breaking down proteins and killing harmful bacteria that might be ingested with food.
When food enters the stomach, it stretches the stomach lining, and this triggers the G cells to release gastrin. Gastrin then travels through the bloodstream and binds to specific receptors on the parietal cells in the stomach lining. This binding activates an enzyme system that leads to the secretion of hydrochloric acid. The acid creates an acidic environment in the stomach, which activates pepsinogen (an inactive precursor) into pepsin, an enzyme that breaks down proteins.
In addition to its role in acid secretion, gastrin also promotes gastric motility, which helps in mixing and moving food through the stomach and into the small intestine. It also stimulates the release of other digestive enzymes from the pancreas, which aid in digestion in the small intestine.
Other hormones like cholecystokinin (CCK) and secretin have roles in digestion, but they do not directly stimulate acid secretion. Cholecystokinin primarily stimulates the gallbladder to release bile and the pancreas to release digestive enzymes, while secretin helps to regulate the pH of the small intestine by stimulating bicarbonate secretion from the pancreas. Neither of these hormones directly influences the parietal cells to release hydrochloric acid.