Topic overview

Start with the big picture

Pathology examines disease through four connected dimensions: etiology (causes), pathogenesis (mechanisms), morphologic changes (structural alterations), and clinical effects. General pathology studies basic cellular and tissue responses to injury across organ systems, while systemic pathology focuses on disorders of particular organs. The field includes anatomic, clinical, molecular, forensic, and experimental branches, with diagnostic work using methods such as microscopy, special stains, immunohistochemistry, and molecular assays. A central task is clinicopathologic correlation: relating structural findings to signs, symptoms, and laboratory abnormalities. By informing diagnosis, prognosis, and therapeutic decisions, pathology also contributes to research, disease surveillance, and public health. The lesson introduces how injury, cellular adaptation, and repair relate to disease and its outcomes.