Histology involves studying the structure of body tissues. Because structure is closely related to function, different tissue types can be distinguished by examining their individual components. Knowledge of the normal histology of the multitude of tissue types within the body is necessary to recognize and understand disease.
The tissue on which a diagnosis is made can be taken from a patient in the operating room, a doctor's office, or an autopsy. An autopsy is an important part of pathology, which seeks to establish the cause of sudden or unexpected death, examine disease progression, and assist police during the investigation of criminal cases. However, most anatomic pathologists deal with tissue samples from living patients. A significant portion of this work is the detection and diagnosis of cancer. A tissue diagnosis is essential before a clinician can start treatment involving major surgery, radiation, or drugs.
