GENERAL HISTOLOGY

Detailed explanation-1: -Parietal cells contain an extensive secretory network (called canaliculi) from which the “hydrochloric acid” is secreted into the lumen of the stomach. 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.

Detailed explanation-2: -A pH gradient was found to exist along the gastric gland, where the pH is 3.0 at parietal cells, i.e., in the deepest regions, and increases to 4.6 at the crypt outlet.

Detailed explanation-3: -Parietal cells (oxyntic cells) are found in the upper portion of the stomach. They are most abundant being found in about 80% of the stomach, mainly in the stomach body and fundus. The oxyntic cells secrete hydrochloric acid and intrinsic factor.

Detailed explanation-4: -Parietal cells within the stomach lining secrete hydrochloric acid that lowers the pH of the stomach. A low pH (1.5 to 2) activates pepsin. Acetylcholine, gastrin, and histamine stimulate the proton pump in parietal cells to release hydrogen ions and decrease pH.