Answer
Hydrochloric acid (HCL) is secreted by the parietal cells of the stomach.
HCl has many functions in the stomach but the following are the most important:
1. It kills microbes
2. It partially denatures proteins in swallowed food
3. It converts the precursor pepsinogen into the active enzyme pepsin.
Work Step by Step
Hydrochloric acid (HCL) of the stomach is secreted by the parietal cells.
Actually, the parietal cells secrete H+ and CL- separately, and they combine to form HCL in the gastric juice. There are several important influences on the production of HCL in the stomach; these include acetylcholine of parasympthetic neurons, histamine (a pracrine released from mast cells) and gastrin released from G cells.
HCl performs many important functions : it kills microbes; it partially denatures proteins, and it converts pepsinogen (the precusor of pepsin) into the enzyme pepsin. These are the three major functions; however, there are others. HCl provides the acidic environment (low pH) that is necessary for pepsin to act--a pH higher than 2.0 is inimical to pepsin catalysis. It is of less importance to gastric activity, but essential to later digestive processes, nevertheless, HCL indirectly promotes the release of bile and pancreatic juice.
