DISEASE

The term pathophysiology, which is the focus of this book, may be defined as the physiology of altered health. The term combines the words pathology and physiology. Pathol­ogy (from the Greekpathos, meaning "disease") deals with the study of the structural and functional changes in cells, tissues, and organs of the body that cause or are caused by disease. Physiology deals with the functions of the human body. Thus, pathophysiology deals not only with the cel­lular and organ changes that occur with disease but also with the effects that these changes have on total body func­tion. Pathophysiology also focuses on the mechanisms of the underlying disease and provides the background for preventive as well as therapeutic health care measures and practices.

A disease has been defined as any deviation from or in­terruption of the normal structure or function of a part, organ, or system of the body that is manifested by a char­acteristic set of symptoms or signs; the etiology, pathology, and prognosis may be known or unknown. The aspects of the disease process include the etiology, pathogenesis, morphologic changes, clinical manifestations, diagnosis, and clinical course