27CHAPTER 2 Body Structure
Objectives
Upon completion of this chapter, you will be able to:
- List and describe the basic structural units of the body.
- Describe the anatomical position of the body.
- Locate the body cavities and abdominopelvic regions of the body.
- Describe terms related to position, direction, and planes of the body and their applications
during radiographic examinations. - Describe common diseases, conditions, and procedures related to several body systems.
- Recognize, define, pronounce, and spell terms correctly.
- Demonstrate your knowledge of this chapter by successfully completing the frames and
reviews.
The human body consists of several structural and functional levels of organization. The complexity of each level
increases from one to the next, because the higher level incorporates the structures and functions of the previous level
or levels. Eventually, all levels contribute to the structure and function of the entire organism. (See Fig. 2–1.) The
levels of organization from the least to the most complex are the
- cellular level,the smallest structural and functional unit of the body;
- tissue level,groups of cells that perform a specialized function;
- organ level,groups of tissues that perform a specific function;
- system level,groups of organs that are interconnected or that have similar or interrelated functions; and
- organism level,collection of body systems that makes up the most complex level—a living human being.