Necrosis

 

Necrosis:-

 

Definition:-

Necrosis is the series of morphological changes that follow cell death in lethally injured of living cells.

·          In which cellular membrane fall apart and cellular enzymes leak out and ultimately digest the cell.

·         Necrosis is caused by various agent such as hypoxia, chemical & physical agents ,microbial agent, immunological injury etc.

Types:-

Types of necrosis based on etiological &morphological appearance.

1) Coagulative Necrosis

2) Liquefactive Necrosis

3) Caseous Necrosis

4) Fat Necrosis

5) Fibrinoid Necrosis

1) Coagulative Necrosis :-

* This is the most common type of necrosis caused by irrversible cell injury.

* It’s mainly caused by sudden stop of blood flow and less often from bacterial &chemical agents.

* The organ commonly affected area are heart,kidney &spleen.

 * Denaturation of all protein and its own lysosomal enzymes are also denatured.

* Later dineted by Leukocytes. For exp- All infarcts expect brain.

2)Liquefactive Necrosis :-

* Tissue get converted into liquid viscous mass.

*It’s due to ischemic injury and fungal or bacterial infection.

*Hydrolytic enzymes caused to tissue degradation &  material become ; semi fluid material (creamy yellow pus ) for eg.- Brain infarets, & abscess cavity.

 3)Caseous Necrosis :-

* This type of Necrosis is found in the centre of foci of tuberculosis infections.

*It’s combine feature of both coagulative & liquefactive necrosis.

*It’s resemble like dry cheese (yellow white colour) soft & granular for eg.-Tuberculosis

4) Fat Necrosis:-

* Fat necrosis mainly occurs in fat rich anatomic location in the body like breast.

*Fat become fat distruction ; calcified to produce chalky white area.

*Calcium deposition around the inflammatory border for eg. – Acute pancreatitis

5) Fibrinoid Necrosis :-

Deposition of fibrin like material

Commonly seen in immune complex mediated vasculitis for eg.- Auto immune disease, Vasculitis peptic ulcer.