Which stomach cells are primarily responsible for adjusting the acidity of the stomach contents?

The cells primarily responsible for adjusting the acidity of stomach contents are the parietal cells. These specialized cells are located within the gastric glands of the stomach lining and play a crucial role in digestion by secreting hydrochloric acid (HCl).

The secretion of hydrochloric acid significantly lowers the pH of the stomach contents, resulting in a highly acidic environment that is essential for activating digestive enzymes, such as pepsinogen, which is converted to pepsin in the presence of acid. This acidic environment also helps to kill harmful bacteria that may enter the stomach with food, providing an important defense mechanism.

In contrast, chief cells are responsible for secreting digestive enzymes like pepsinogen, while neck cells (or mucous neck cells) produce a less viscous mucus that protects the gastric epithelium. Surface mucous cells also contribute to the protective mucus layer but do not directly influence acidity. Thus, parietal cells play the critical role in regulating stomach acidity, which is essential for effective digestion and maintaining overall gastric function.