Unit 4
Body Systems and Digestion

To understand how food works in the body, you need a basic understanding of the major body systems and of the process of digestion itself. These topics form the subject of this unit.

Objectives

After completing this unit, you should be able to

1. identify and describe, briefly, the major body systems listed below.
   • cellular
   • cardiovascular
   • immune
   • hormonal
   • nervous
   • excretory
2. describe chemical and mechanical digestion starting at the mouth and finishing at the small intestine.
3. identify the anatomy and organs of the gastrointestinal tract.
4. describe the large intestine’s role in digestion.
5. describe mechanical digestion.