The best-known component of gastric juice is hydrochloric acid. Hydrochloric acid is produced by the parietal cells or oxyntic cells of the stomach. These glands open into the gastric pits on the gastric mucosal surfaces.
Gastric hydrochloric acid is secreted from the highly specialized parietal cells located in the corpus of the stomach, generating a H+ concentration in the gastric juice that is 3 million times greater than that in blood and tissue. The process is controlled by a complex system of endocrine cells and neurons.
Hydrochloric acid secretion assists protein digestion by activating pepsinogen to pepsin, renders the stomach sterile against orally-ingested pathogens, prevents bacterial or fungal overgrowth of the small intestine, encourages the flow of bile and pancreatic enzymes, and facilitates the absorption of a variety of nutrients, including folic acid, ascorbic acid, beta-carotene, non-heme iron, and some forms of calcium, magnesium, and zinc.
The secretion of hydrochloric acid by the stomach plays an important role in protecting the body against pathogens ingested with food or water. A gastric acid pH of 1 to 2 is deleterious to many microbial pathogens. The gastric juice is the first line of defense against infection throughout the gastrointestinal tract.
Approximately 2 L of hydrochloric acid is produced daily. The pH level in the stomach depending on factors such as food intake, stress, and medications or supplements. An increase in hydrochloric acid and decreasing pH level also signal gastric motility to turn on to move the partially digested bolus of food along and help kill bacteria normally ingested with food.
Roles of hydrochloric acid in stomach
