The digestive system is made up of key parts, each of which has a different function. Food passes through most of these parts in a journey from the mouth to the anus.

The mouth is where digestion begins, and it breaks down food into smaller particles. Read more about the functions and biological structure of the mouth.

Research over the years has provided insight into this organ's structure and various functions. As essential components of an effective adaptive immune system, the thymus develops responsive T ...