The enzyme in the saliva digests starch to maltose. The tongue rolls the food into small round masses called boluses, then pushes the bolus into the pharynx for swallowing.
The stomach wall is made up of thick circular and longitudinal muscle layers. These muscles contract and relax producing movement that aids in the mixing of the contents of the stomach. This mixing is known as churning and results in the formation of a fluid called chyme.
The remaining semi-solid waste material is then passed to the rectum where it is stored temporarily and eventually eliminated from the body as feces through the anus as the sphincter muscles relax.
