AAMC FL Practice Exam

Which cells in the stomach are responsible for producing hydrochloric acid (HCl)?

1. Chief cells

2. Parietal cells

3. Mucous cells

4. Gastric cells

The correct answer is: Parietal cells

Parietal cells are specialized cells located in the lining of the stomach that are primarily responsible for the production of hydrochloric acid (HCl). These cells are found in the gastric glands of the stomach and play a crucial role in the digestive process. Hydrochloric acid serves several important functions: it creates an acidic environment in the stomach, which is essential for activating the enzyme pepsinogen into its active form, pepsin, facilitating protein digestion. Additionally, the acidity helps to kill ingested pathogens, contributing to the body's defense mechanisms. While other cell types in the stomach serve important functions, they do not produce hydrochloric acid. Chief cells, for instance, secrete digestive enzymes, particularly pepsinogen; mucous cells produce mucus to protect the stomach lining; and gastric cells is a more general term that may refer to multiple cell types without specifying function. Thus, the specific role of parietal cells in HCl production makes them the correct choice for this question.