What is Pathology?

Pathology is scientific study of structural and functional changes in disease or the alterations that occur when abnormal influences (bacteria, viruses etc.) affect cells, tissues, or body systems. More specifically, pathology may be defined as the “scientific study of the molecular, cellular, tissue, or organ system response to injurious agents or adverse influences.” For more than a hundred years, pathology has been one of the “keystones” of medicine. As an academic subject, it is taught as part of the veterinary curriculum to prepare the student for courses in clinical medicine and surgery. It serves as a “bridge” or “link” between the preclinical subjects (anatomy, physiology, etc.) and the courses in clinical medicine. Actually, pathology provides a logical means of relating the knowledge of normal structure and function (anatomy and physiology) to abnormal structure and function as encountered in a diseased animal. Thus, the factual background or knowledge needed for logical reasoning when solving real-life clinical problems is provided. It should be emphasized that pathology, as the scientific study of disease, follows the morbid process from its inception to its termination, and investigates the lesions produced. Therefore, a sound knowledge of pathology is the foundation of a solid understanding of disease as it occurs in the living patient.

Pathology has its roots deeply implanted in medical history. The earliest observers, from Celsus (about 30 B.C. – A.D. 38) to Morgagni in the 18th century, based their work upon the naked-eye appearances of diseased individuals and organs. However, the investigation of changes at cellular level could start only after development of  technique of light microscopy under the Germanic School of Pathology, headed by Virchow (1821-1905). Today, technological advances have made it possible to study disease through several pathological techniques. Some of the key techniques available in pathology include light microscopy, electron microscopy, micro-dissection, immunological techniques, ultracentrifugation, electrophoresis, chromatography, radioactive isotope technology, tissue culture, etc.

Pathology is a broad discipline and comprises several sub-disciplines.  Some of the key ones are:

• Biochemistry
• Clinical Pathology
• Hematology and Coagulation Assays
• Immunoassays
• Histopathology
• Microbiology