Hydrochloric acid is secreted by which of the secretory cells of the stomach? Serous Parietal cells Chief cells Mucous neck cells
The Correct Answer and Explanation is:
The correct answer is Parietal cells.
Explanation:
Hydrochloric acid (HCl) is produced and secreted by the parietal cells of the stomach. These cells are located primarily in the lining of the stomach, particularly in the gastric glands found in the mucosa. The secretion of HCl is crucial for digestion, as it serves several essential roles in the stomach:
- Activation of Pepsinogen: The acidic environment created by HCl activates pepsinogen, an inactive enzyme secreted by the chief cells, into its active form, pepsin. Pepsin then helps in the breakdown of proteins into smaller peptides, initiating protein digestion.
- Denaturation of Proteins: The acidic pH of HCl helps in denaturing proteins, unraveling their structures and making them easier to digest by enzymes like pepsin.
- Protection against Pathogens: The low pH in the stomach acts as a barrier to microorganisms. It kills many pathogens and bacteria that might be ingested along with food, preventing infections.
- Increased Solubility of Minerals: The acidic environment facilitates the solubility of minerals like calcium and iron, improving their absorption.
The other secretory cells:
- Serous cells: These cells produce a watery secretion rich in enzymes, but not HCl. They are mostly found in the salivary glands, where they help in the initial breakdown of food.
- Chief cells: Chief cells secrete pepsinogen, which is an inactive enzyme that is converted to pepsin in the acidic environment of the stomach. They do not secrete hydrochloric acid.
- Mucous neck cells: These cells secrete mucus that protects the stomach lining from the acidic environment and mechanical damage. They do not produce HCl.
Therefore, the parietal cells are specifically responsible for secreting hydrochloric acid in the stomach.
