![]() Gastric acid secretion is produced in several steps. In addition, many microorganisms are inhibited or destroyed in an acidic environment, preventing infection or sickness.Ī typical adult human stomach will secrete about 1.5 liters of gastric acid daily. The low pH activates pepsinogen into the enzyme pepsin, which then aids digestion by breaking the amino acid bonds, a process called proteolysis. The gastric chief cells of the stomach secrete enzymes for protein breakdown (inactive pepsinogen, and in infancy rennin). ![]() Peptide bonds, which comprise proteins, are labilized. The highly acidic environment in the stomach lumen degrades proteins (e.g., food). The parietal cell releases bicarbonate into the bloodstream in the process, which causes a temporary rise of pH in the blood, known as an alkaline tide. The pH of gastric acid is 1.5 to 3.5 in the human stomach lumen, a level maintained by the proton pump H +/K + ATPase. Parietal cells contain an extensive secretory network (called canaliculi) from which the "hydrochloric acid" is secreted into the lumen of the stomach. The secretion is a complex and relatively energetically expensive process. The primary active component of gastric acid is hydrochloric acid (HCl), which is produced by parietal cells in the gastric glands in the stomach. The pancreas further produces large amounts of bicarbonate and secretes bicarbonate through the pancreatic duct to the duodenum to neutralize gastric acid passing into the digestive tract. These cells also produce mucus – a viscous barrier to prevent gastric acid from damaging the stomach. Other cells in the stomach produce bicarbonate, a base, to buffer the fluid, ensuring a regulated pH. Gastric acid is regulated in feedback systems to increase production when needed, such as after a meal. With a pH between 1 and 3, gastric acid plays a key role in digestion of proteins by activating digestive enzymes, which together break down the long chains of amino acids of proteins. ![]() Gastric acid, gastric juice, or stomach acid is a digestive fluid formed within the stomach lining. Digestive fluid formed in the stomach Determinants of Gastric Acid Secretion
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