Gastric Glands are present in the wall of the stomach that release secretions for digestion of food. The gastric glands produce gastric juice which contains three substances: 1. Hydrochloric acid 2. Pepsin Enzyme 3. Mucus. Due to presence of HCl, the gastric juice is acidic in nature . In acidic medium, the enzyme pepsin begins the digestion of proteins present in food to form smaller molecules . HCl kills any bacteria which may enter the stomach. The mucus helps to protect the stomach wall from its own secretion of HCl.