THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Pepsin is a stomach enzyme that serves to digest proteins found in ingested food. Gastric chief cells secrete pepsin as an inactive zymogen called pepsinogen. 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.

Detailed explanation-2: -Pepsin is an endopeptidase that initiates the process of protein digestion in the stomach. Pepsin action results in the release of small peptides and amino acids (peptones) that, as noted above, stimulate the release of gastrin from antral G cells; these peptones also stimulate CCK release from duodenal I cells.

Detailed explanation-3: -Due to this action, pepsin belongs to a family of enzymes known as endopeptidases. The product of protein hydrolysis catalyzed by pepsin are polypeptide fragments of high molecular weight, which were originally named proteoses and peptones.