Physiology An Illustrated Review PDF Free Download
Understanding human physiology, the function of the body, from subcellular processes to those of the whole organism, is essential for any health professional. Health depends upon the proper functioning of all body systems. When there is a malfunction, our bodies have many methods of self-correction, but they also benefit from interventions by skilled health professionals. In order to intervene successfully, the health professional has to correctly diagnose the malfunction, provide the appropriate treatment, and monitor and recognize when function returns to normal. This chain of events is all dependent on an understanding of physiology. Our understanding of physiology has developed over the last century and a half due to the efforts of thousands of medical scientists. The French physiologist, Claude Bernard, summarized his understanding of the functions of the body with a book entitled, “The Basis of Experimental Medicine” 150 years ago. His best known concept is that of the internal environment and its relative constancy.
All cells in the body are bathed in a dilute salt solution similar to that of sea water eons ago. Our bodies regulate the composition of this solution to maintain the viability of all our cells. One part of physiology is the study of how the body regulates the composition of this solution. About 100 years ago, Walter Cannon, MD, coined the term “homeostasis” to describe this constancy. Such control is not static, but requires energy to maintain the steady state of the bathing solution. About 50 years ago, Arthur Guyton, MD, the great physiology teacher, and others applied engineering control systems theory to physiological processes. Negative feedback control is one concept they applied to physiological systems. So physiological understanding continues to grow.