The digestive system breaks down food through mechanical and chemical digestion. Teeth and saliva begin breaking down food, then the esophagus transports it to the stomach where it is further broken down and mixed. The small intestine is where most digestion occurs through the action of enzymes and bile from the liver and gallbladder. Undigested waste passes to the large intestine and is removed from the body along with other waste products by the excretory system, including the kidneys which filter wastes and the bladder which stores urine.