Organization and General Plan of the Body
The human body is a precisely structured container of chemical reactions. Have you ever thought of your-self in this way? Probably not, and yet, in the strictly physical sense, that is what each of us is. The body consists of trillions of atoms in specific arrangements and thousands of chemical reactions proceeding in a very orderly manner. That literally describes us, and yet it is clearly not the whole story. The keys to understanding human consciousness and self-awareness are still beyond our grasp. We do not yet know what enables us to study ourselves—no other animals do, as far as we know—but we have accumu-lated a great deal of knowledge about what we are made of and how it all works. Some of this knowledge makes up the course you are about to take, a course in basic human anatomy and physiology.
Anatomy is the study of body structure, which includes size, shape, composition, and perhaps even coloration. Physiology is the study of how the body functions. The physiology of red blood cells, for exam-ple, includes what these cells do, how they do it, and how this is related to the functioning of the rest of the body. Physiology is directly related to anatomy. For example, red blood cells contain the mineral iron in molecules of the protein called hemoglobin; this is an aspect of their anatomy. The presence of iron enables red blood cells to carry oxygen, which is their function. All cells in the body must receive oxygen in order to function properly, so the physiology of red blood cells is essential to the physiology of the body as a whole.
Pathophysiology is the study of disorders of func-tioning, and a knowledge of normal physiology makes such disorders easier to understand. For example, you are probably familiar with the anemia called iron-deficiency anemia. With insufficient iron in the diet, there will not be enough iron in the hemoglobin of red blood cells, and hence less oxygen will be trans-ported throughout the body, resulting in the symp-toms of the iron-deficiency disorder. This example shows the relationship between anatomy, physiology, and pathophysiology.
The purpose of this text is to enable you to gain an understanding of anatomy and physiology with the emphasis on normal structure and function. Many examples of pathophysiology have been included, however, to illustrate the relationship of disease to normal physiology and to describe some of the proce-dures used in the diagnosis of disease. Many of the examples are clinical applications that will help you begin to apply what you have learned and demonstratethat your knowledge of anatomy and physiology will become the basis for your further study in the health professions.