Question

cells in the wall of the stomach produce pepsinogen, which plays a role in protein digestion. why dont these cells digest themselves?

Explanation:

Pepsinogen is secreted in an inactive form. It is activated to pepsin in the acidic environment of the stomach lumen, not in the cells that produce it. Also, the cells are protected by a layer of mucus which acts as a physical barrier preventing self - digestion.

Answer:

Pepsinogen is secreted in an inactive form and cells are protected by mucus layer.