Which gastric mucosal cell type is primarily responsible for acid secretion?

Which gastric mucosal cell type is primarily responsible for acid secretion?

• A. Chief cells
• B. Mucous neck cells
• C. G cells
• D. Parietal cells

Answer: (C)

Acid secretion is carried out primarily by parietal (oxyntic) cells in the gastric glands. These cells have the H+/K+-ATPase proton pumps on their apical membrane that actively secrete hydrogen ions into the stomach lumen, forming hydrochloric acid. Parietal cells also secrete intrinsic factor, which is essential for vitamin B12 absorption. Gastrin-secreting cells (G cells) stimulate acid production indirectly by releasing gastrin, which increases parietal cell activity and can enhance histamine release from ECL cells; histamine then acts on parietal cells to promote acid secretion. However, the actual acid is produced by the parietal cells, not by the G cells themselves. Chief cells secrete pepsinogen, and mucous neck cells secrete mucus to protect the mucosa.

Acid secretion is carried out primarily by parietal (oxyntic) cells in the gastric glands. These cells have the H+/K+-ATPase proton pumps on their apical membrane that actively secrete hydrogen ions into the stomach lumen, forming hydrochloric acid. Parietal cells also secrete intrinsic factor, which is essential for vitamin B12 absorption.

Gastrin-secreting cells (G cells) stimulate acid production indirectly by releasing gastrin, which increases parietal cell activity and can enhance histamine release from ECL cells; histamine then acts on parietal cells to promote acid secretion. However, the actual acid is produced by the parietal cells, not by the G cells themselves. Chief cells secrete pepsinogen, and mucous neck cells secrete mucus to protect the mucosa.