the scientific study of the functional and physiological changes that occur in the body as a result of disease or injury. It explores the underlying mechanisms and processes — from cellular and molecular alterations to organ dysfunction and systemic disturbances — that contribute to the onset, progression, and complications of a disease or condition. Understanding pathophysiology bridges the gap between basic science and clinical practice by explaining how and why symptoms and signs develop.
Example
In chronic obstructive pulmonary disease (COPD), pathophysiology includes chronic inflammation of the airways, loss of elastic recoil in lung tissue, and mucus hypersecretion. These changes lead to airflow limitation, impaired gas exchange, and symptoms such as shortness of breath and chronic cough.