Question

The cells of the epithelial lining in the vertebrate stomach are not damaged by HCl because of

• A. Mucus secretion covering the epithelium
• B. Neutralization of HCl by alkaline gastric juice
• C. HCl being too dilute
• D. Epithelium being resistant to HCl

Answer 1

The correct option is A Mucus secretion covering the epithelium

The mucosa of the stomach has gastric glands. Gastric glands have three major types of cells namely mucous neck cells, which secrete mucus that protects the stomach wall from the acidic condition. Peptic or chief cells, which secrete the proenzyme pepsinogen which gets activated in the presence of acidic conditions and convert into the pepsin for protein digestion. Parietal or oxyntic cells, which secrete HCl and intrinsic factor (factor essential for absorption of vitamin $B_{12}$). The mucus and bicarbonates present in the gastric juice play an important role in lubrication and protection of the mucosal epithelium from excoriation by the highly concentrated hydrochloric acid.