The digestive system begins at the mouth and is approximately 30 feet long. It has three main functions: digestion of food into nutrients, absorption of nutrients into the bloodstream, and elimination of solid wastes. Food enters the mouth where it is broken down by teeth and mixed with saliva from salivary glands. It then moves to the stomach through the esophagus where acids and enzymes further break it down. Nutrients from the food are then absorbed through the small intestine walls and transported throughout the body by the bloodstream. Undigested waste moves into the large intestine where water is absorbed, before waste is stored in the rectum and expelled from the body through the anus.