Basic Principles of Cell Injury and Adaptation-I

Abstract

Cell injury and adaptation are fundamental concepts in pathology, exploring how cells respond to stress and damage. Cell injury occurs when cells face stressors that disrupt their normal function and structure, while adaptation refers to the changes cells undergo to survive such stress. Homeostasis is the maintenance of a stable internal environment, crucial for cell survival. Feedback systems, which can be negative or positive, help regulate homeostasis by adjusting cellular activities. Causes of cellular injury include physical trauma, toxins, infections, and ischemia. The pathogenesis of cell injury involves damage to critical cellular components like the cell membrane, mitochondria, ribosomes, and nucleus. Morphologically, cells exhibit adaptive changes to counteract injury. Atrophy is the reduction in cell size due to decreased workload or adverse conditions. Hypertrophy, on the other hand, involves an increase in cell size often due to increased demand. Hyperplasia refers to an increase in cell number, usually as a response to a stimulus. Metaplasia is the reversible replacement of one cell type with another, often as a protective mechanism. Dysplasia is characterized by abnormal growth and development of cells, potentially leading to neoplasia. Understanding these principles provides insight into how cells maintain function and integrity under various physiological and pathological conditions