Which cells in the stomach secrete hydrochloric acid?

• A. Chief cells
• B. Parietal cells
• C. Goblet cells
• D. Enterocytes

Answer: (B)

Parietal cells are responsible for secreting hydrochloric acid in the stomach. These cells, located mainly in the fundus and body of the stomach within the gastric glands, use a proton pump (H+/K+ ATPase) to actively transport hydrogen ions into the stomach lumen. Chloride ions accompany them, joining with the hydrogen to form hydrochloric acid right in the gastric juice. This strong acidity helps activate pepsinogen to pepsin, denature proteins, and kill or inhibit swallowed microbes. Parietal cells also produce intrinsic factor, important for vitamin B12 absorption, and their activity is influenced by signals like gastrin, histamine, and acetylcholine.

For context, other stomach cells have different roles: chief cells secrete pepsinogen, goblet cells produce mucus to protect the lining, and enterocytes are absorptive cells in the small intestine, not the stomach.