What are the functions of the gastric gland present in the wall of the stomach?

Gastric juice contains three substances.

These are hydrochloric acid, the enzyme pepsin, and mucus.

Functions: 

(a) Hydrochloric acid:

The main function of hydrochloric acid in food is to kill bacteria that may enter the stomach with food. It also helps in creating the acidic environment or acidic pH required for the activation of inactive pepsinogen.

(b) Pepsin:

It digests proteins present in food and converts them into smaller molecules.

Pepsin helps in the digestion of proteins into amino acids.

(c) Mucus:

It helps protect the stomach's inner layer from its own secretions of hydrochloric acid. It helps to protect the stomach wall from the corrosive effect of hydrochloric acid.

If the mucus is not secreted by the gastric glands then the gas will damage the inner lining of the stomach and lead to ulcers in the stomach.