Chief cells are responsible for the secretion of which substance?

Chief cells, located in the gastric glands of the stomach, play a crucial role in the digestive process by secreting pepsinogen. Pepsinogen is an inactive precursor to the enzyme pepsin, which is vital for protein digestion. Once pepsinogen is secreted into the gastric lumen, it is activated by the acidic environment of the stomach, primarily due to hydrochloric acid produced by parietal cells. This activation allows pepsin to break down proteins into smaller peptides, facilitating further digestion.

In essence, the function of chief cells directly supports the digestive process by providing the necessary enzymes that will become active in the acidic conditions of the stomach. This differentiation in function among the cells of the gastric glands is key to the overall efficiency of digestion.