INTRODUCTION TO ANATOMY AND PHYSIOLOGY
Anatomy is the study of the structure of the body, its organs, and the relationship
of its parts. There are many subdivisions or branches of this science. Physiology is the
study of the functions and activities of the parts of the body. This science also has
many subdivisions. In this lesson, both anatomy and physiology are presented in the
discussion of the structure and function of the various systems of the human body.
These systems are closely interrelated and interdependent.
The cell is the basic functioning unit in the composition of the human body and all
other living organisms. It is microscopic in size. The body is composed of billions of
cells that vary in size and shape. A simple cell includes the cell membrane or cell wall,
nucleus, and cytoplasm (see figure 1-1). In addition to these parts, cells include many
other smaller parts.
Figure 1-1. Simple cell.