17/08/2023
⭕General pathology:-
↔️Necrosis
⬇️Definition : is a form of cell death in which cellular membranes fall apart, and cellular enzymes leak out and ultimately digest the cell.
⬇️Necrosis elicits a local host reaction, called inflammation, that is induced by substances released from the dead cells and which serves to eliminate the debris and start subsequent repair process.
⬇️The enzymes responsible for digestion of the cells are derived from lysosomes and may come from the dying cells themselves or from leukocytes recruited as part of the inflammatory reaction.
⬇️Necrosis often is the culmination of the reversible cell injury that cannot be corrected.
⬇️Biochemical mechanisms of necrosis vary with different injurious stimuli. these mechanisms include :
🔸Failure of energy generation in the form of ATP because of reduced oxygen supply or mitochondrial damage.
🔸Damage to cellular membranes including plasma membrane and lysosomal membranes, which results in leakage cellular contents including enzymes.
🔸Irreversible damage to cellular lipids, Proteins, and nucleic acids, which may be caused by the reactive oxygen species (ROS) and others.
⬇️Necrosis is morphological manifestion of the accidental cell death.
⬇️Necrosis is rapid, uncontrolable cell death.
⬇️Necrosis is the major pathway of the cell death in many commonly encountered injuries such as those resulting from ischemia, esposure to toxins,various infection and trauma.
⬇️Necrosis traditionally considered the inevitable end result of severe damage that is beyond salvage and is not thought to be regulated by specific signals or biochemical mechanisms.
⬇️Necrosis happens accidentally because the injury is too severe to be repaired and many cellular constituents simply fail or fall apart.
⬇️Necrosis always an indication of a pathologic process.
🔜Morphology of necrosis.
⛔Robbins basic pathology - tenth edition -
