The digestive tract, which is also known as the alimentary canal, is a long tube extending from the mouth to the anus. This tube is composed of the mouth, pharynx, esophagus, stomach, small intestines, and large intestines. Along the alimentary canal are various glands which secrete substances which contribute to the process of digestion.
Digestion starts when food is chewed in the mouth.
Chewing breaks up food so that it has more exposed surface area. The tongue moves food under the teeth so that it can be chewed. The tongue has taste buds which convey information to the brain about the food. It also aids in swallowing food. The act of chewing is called mastication.