Question

HCl is secreted by
A. Zymogen cells
B. Oxyntic cells
C. Kupffer cells
D. Mucous cells

Answer 1

Hint: HCl stands for hydrochloric acid. It is secreted by stomach cells. HCl forms gastric juice along with digestive enzymes like lipase and pepsin and others. Gastric juice plays an important role in digestion of food. HCl in gastric juice breaks down the food, while the lipase and pepsin digest the lipids and proteins respectively. The acidic nature of HCl also kills the bacteria inside the stomach.

Complete answer:
• HCl is an acidic solution produced by the stomach. It is colourless and watery with a pH of 1 to 2. Due to its lower pH, it is highly corrosive in nature.
• HCl can be dangerous and damaging for the stomach lining. Hence, the body produces a mucoid barrier in order to protect the stomach lining from the corrosive action of HCL. However, this protective mucous barrier can get damaged in some people due to many reasons. In such cases, HCl can damage the stomach lining causing an ulcer known as stomach ulcer.
• HCl is secreted by the parietal cells lining the stomach. Parietal cells are also known as Oxyntic cells or delomorphous cells. These are epithelial cells present in the gastric glands of the stomach.
• Zymogen cells are found in gastric glands towards their base. They secrete digestive enzymes such as pepsinogen, but they do not secrete HCl.
• Kupffer cells are types of macrophages that are found in the liver. They help in breakdown of RBCs. They do not secrete HCl.
• Mucous cells are present in mucous glands. They produce a thick mucus that forms a coating to protect the stomach lining from HCl. Mucous cells do not produce HCl.

Hence, the correct answer is option (B).

Note: HCl production is under the control of the nervous system and hormones. The vagus nerve of parasympathetic nervous system (PNS) alongwith hormone gastrin stimulates the parietal cell of stomach to secrete HCl and other components of gastric juice. The vagus nerve and gastrin can act directly on parietal cells or indirectly by acting on Enterochromaffin-like cells (ECL) of the stomach. ECL releases another hormone called histamine that makes the parietal cells release HCl.