What is the digestive system? It is a body system that turns food into nutrients for cells to eat. The digestive system has three accessory organs and a digestive tract. The digestion starts in your mouth. The teeth grind and chew the food. The tongue tastes the food and sends signals to the brain. The 3 salivary glands secrete saliva containing the enzyme ptyalin which turns food into starch. It also contains lysozymes which are proteins that kill bacteria present in food. The resulting mixture turns into bolus which is swallowed down your esophagus or gullet. The esophagus goes through peristalsis and bolus goes into the stomach. The stomach secretes gastric juice which contains the enzyme pepsin and hydrochloric acid. The stomach contracts and relaxes and turns bolus into chyme. The chyme is sent to the small intestine. The small intestine has 3 parts: the duodenum, the jejunum and the ileum. Vili in the small intestine absorb and digest the chyme. Undigested chyme passes on to the large intestine. The large intestine has several parts: the cecum, the appendix, the transverse colon, the ascending colon, the descending colon, the sigmoid colon, the rectum, and the anus. The large intestine absorbs the undigested chyme. The feces is then excreted through the body. The liver, pancreas, and gallbladder help as accessory organs in digesting food.