The knowledge of physiology continues to unravel new mysteries of body functions.It is the link between the basic sciences and medicine. The great beauty of physiology is that it integrates the  knowledge across many levels, including biochemistry, cell physiology, organ systems and the body as a whole. 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 physiological discoveries have played an important  role in the progress of medicine and the practice of today has evolved from the “theories” of yesterday.