Stomach secretes three digestive juices, viz. mucus, proenzyme pepsinogen and hydrochloric acid. Mucus is secreted by mucus membrane, and hydrochloric acid is secreted by oxyntic cells. Hydrochloric acid kills any germs in food and makes the medium in stomach acidic. Acidic medium is necessary for working of gastric enzyme. Pepsinogen changes to pepsin which digests protein into peptide. Rennin is secreted in small children and helps in digestion of milk protein.
