What Students Need To know About Tissue Damage And Cell Injuries.

The fundamental pathogenesis of cell injury is a perturbation of homeostasis. Cell injury is initiated at the molecular level, and, although the specific causes are diverse and numerous, the basic mechanisms can be categorized as follows: • Adenosine triphosphate (ATP) depletion • Permeabilization of cell membranes • Disruption of biochemical pathways, especially those of protein synthesis • DNA damage Although certain injurious agents can cause ATP depletion, membrane damage, pathway disruption, or DNA damage in isolation, more often there is interplay among these basic mechanisms. Anything that decreases the supply of oxygen and other nutrients to the cell or that damages mitochondria directly halts oxidative phosphorylation, leading to rapid depletion of ATP, even in those cells that can switch to anaerobic glycolysis. The ATP depletion results in additional cell damage by causing failure of energy-dependent enzymes, in particular the cell membrane adenosine triphosphatase ion pumps that con