Human physiology is the science of mechanical, physical and biochemical functions of humans and serves as the foundation of modern medicine. As a dicipline it connects science, medicine and health and create a framework for understanding how the human body adapts to stress, physical activity and disease. The study of physiology integrates knowledge across many levels, including biochemistry, cell physiology, organ systems and the body as a whole. Contemporary research in human physiology explores new ways to maintain or improve the quality of life, development of new medical therapies and interventions and charting the unanswered questions about how the human body works. It is interesting to note that many of the outstanding physiologists have been well-known physicians. We are now aware of tremendous body of physiological knowledge that has its origin in the study of disease. In turn, the exciting progress in medicine, dentistry and health care in this centuary has largely originated from the application of physiology to clinical medicine. "The physiology of today is the medicine of tomorrow".