Foundations of General Pathology: Cell Injury, Inflammation, and Disease Processes

Abstract

General pathology is the study of the fundamental mechanisms by which cells and tissues respond to injury, and it underlies the understanding of all disease. This paper reviews the foundations of general pathology, focusing on cell injury and death, the inflammatory response, and the broad categories of disease process. A review-based approach is adopted, drawing on the standard texts of pathology. The analysis sets out the causes and sequence of cell injury, distinguishing reversible injury and cellular adaptation from irreversible injury culminating in cell death, and it contrasts the two principal forms of cell death, necrosis and apoptosis. It then describes the inflammatory response, the body's reaction to injury and infection, outlining the vascular and cellular events of acute inflammation and its cardinal signs, and distinguishing acute from chronic inflammation. Finally, it situates these processes within the broad categories of disease, inflammatory and infective, degenerative, neoplastic, immunological, circulatory, and genetic or developmental, that structure the study of pathology. The study finds that cell injury and inflammation are the unifying processes underlying the great majority of disease, that their outcomesdepend on the nature and severity of the injurious stimulus and the capacity of the tissue to adapt and repair, and that an understanding of these foundations is essential to the interpretation of specific diseases. It concludes that general pathology provides the conceptual framework, linking cause, mechanism, structural change, and clinical consequence, on which the study of medicine rests. Certain quantitative figures are illustrative. KEYWORDS: General Pathology, Cell Injury, Necrosis, Apoptosis,Inflammation, Cellular Adaptation, Disease Process, Pathogenesis