Overview Introduction Cells constantly interact with their environment and try to maintain homeostasis cells respond to stress (e.g., physiologic and toxic) via adaptation to maintain viability and function cell injury results when the cell can no longer adapt to the stress, which can be login to view 5 more bullets General mechanism of cell injury ATP depletion leads to reduced Na+/K+ ATPase activity causing login to view 1 more bullet ↑ anaerobic glycolysis which subsequently leads to login to view 2 more bullets reduced calcium pump activity which login to view 1 more bullet reduced protein synthesis mitochondrial damage can result from hypoxia, reactive oxygen species (ROS), and ↑ intracellular calcium levels and leads to increased mitochondrial permeability which causes login to view 3 more bullets DNA damage that is irreparable results in apoptosis login to view 1 more bullet Etiologies of cell injury includes hypoxia hypothermia can mitigate hypoxic injury by decreasing cellular metabolism and slowing reperfusion ischemia toxin-induced (e.g., ethanol and cigarette smoking) infectious agents genetic abnormalities aging imbalances in nutrition physical causes (e.g., trauma) Findings in Reversible and Irreversible Cellular Injury Reversible Irreversible Morphological findings cellular swelling nuclear chromatin clumping ribosomal detachments econdary to decreased protein synthesis membrane blebbing fatty change Morphological findings plasma membrane damage lysosomal rupture autolysis ↑mitochondrial permeability changes of the nucleus include pyknosis karyorrhexis karyolysis