Necrosis

There are many causes of necrosis including Injury , Infection , Cancer , Infarction , and Inflammation . Necrosis is caused by special Enzyme s that are released by Lysosome s 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 set off 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.

MORPHOLOGIC PATTERNS

There are five distinctive morphologic patterns of necrosis:

Coagulative necrosis - typically seen in Hypoxic environments (e.g. Myocardial Infarction , infarct of the Spleen ). Cell outlines remain after cell death and can be observed by light Microscopy .

Liquefactive necrosis - is associated with cellular destruction and Pus formation (e.g. Pneumonia )

Caseous necrosis - is a mix of coagulative necrosis and liquefactive necrosis (e.g. Tuberculosis )

Fatty necrosis - results from the action of Lipases on fatty tissues (e.g. Acute Pancreatitis , Breast tissue necrosis)

Fibrinoid necrosis - caused by Immune -mediated Vascular damage. It is marked by deposition of Fibrin -like Proteinaceous material in Arterial walls, which appears smudgy and Acidophilic on light microscopy.

ARACHNOGENIC NECROSIS

Spider Bite s are cited as causing necrosis in some areas. These claims are widely disputed, but experts say the possibility is still there. Examples include:

Brown Recluse Spider s in the midwestern United States

White-tailed Spider s in Australia

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Necrosis