Necrosis is the name given to unprogrammed death of cells and living tissue.
It is less orderly than apoptosis, which are part of programmed cell death.
In contrast with apoptosis, cleanup of cell debris by phagocytes of the immune system is generally more difficult, as the disorderly death generally does not send cell signals which tell nearby phagocytes to engulf the dying cell.
This lack of signalling makes it harder for the immune system to locate and recycle dead cells which have died through necrosis than if the cell had undergone apoptosis.
The release of intracellular content after cellular membrane damage is the cause of inflammation in necrosis.
There are many causes of necrosis including injury, infection, cancer, infarction, toxins and inflammation.
Severe damage to one essential system in the cell leads to secondary damage to other systems, a so-called "cascade of effects".
Necrosis can arise from lack of proper care to a wound site.
Necrosis is accompanied by the release of special enzymes, that are stored by lysosomes, which are capable of digesting cell components or the entire cell itself.
The injuries received by the cell may compromise the lysosome membrane, or may initiate an unorganized chain reaction which causes the release in enzymes.
Unlike in apoptosis, cells that die by necrosis may release harmful chemicals that damage other cells.