The digestive system includes all of the organs and structures that aid in the digestion and elimination of food. It includes the gastrointestinal tract, also known as the alimentary canal, as well as other accessory organs. The gastrointestinal tract includes all of the structures and organs extending from the mouth to the anus. This includes the mouth, pharynx, esophagus, stomach, intestines, rectum, and anus. The accessory organs are all of the organs that aid in digestion, such as the liver, gallbladder, and pancreas.