The effects of disease on body functions; the physiology of altered function seen in disease. ("Patho-" is a combining form denoting any disease state, and "physiology" refers to the study of the processes and functioning of the human body.)
Pathophysiology is the study of the disturbance of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from a disease or abnormal syndrome or condition that may not qualify to be called a disease. An alternate definition is "the study of the biological and physical manifestations of disease as they correlate with the underlying abnormalities and physiological disturbances."Craig Scanlon, Egan's Fundamentals of Respiratory Therapy, St. Louis, 1999, p. 1186.