Irrversible Cell Injury Flashcards
What is irreversible cell injury ?
Severe cell injury that the cell can NOT recover after the removal of adverse influence .
Necrosis
It is changes that accompany the cell death , generated by degradative action of enzymes released out of lysosomes of the dying cell itself OR the leukocytes (WBCs)
The major characteristic of necrosis is :
The cell’ s inability to maintain plasma membrane integrity THEN leakage of intracellular proteins
Necrosis detection in MI & hepatitis :
- Necrotic myocytes release certain isoform of creatine kinase and contractile protein troponin within the circulation
- Necrotic hepatocytes release alkaline phosphatase and transaminases (GPT and GOT )
Necrosis appearance ultrastructurally :
- Fragmentation of plasma and organelles membrane
- Myelin figures
- Lysosomes rupture
- Nuclear condensation or dissolution
- ER swelling with the loss of ribosomes
6.mitochondrial dilatation
Necrosis appearance in LM :
- Increased cytoplasmic eosinophilia ( eosin binds with denatured cytoplasmic proteins )
- Glassy homogenous appearance ( loss of glycogen particles )
- Vacuolated cytoplasm ( degradation of organelles )
- Myelin figures ( replacement of dead cells usually )
Necrosis patterns :
- Coagulative necrosis
- Liquefactive necrosis
- Caseous necrosis
- Fat necrosis
- Fibrinoid necrosis
- Gangrene necrosis
Coagulative necrosis is characterised by :
Preservation of tissue architecture
Coagulative necrotic cells appear eosinophilic and anucleated ( karyolysis )
General mechanism of coagulative necrosis :
- Proteins denaturation and Inhibition of enzyme activity
- leading to blocking of proteolysis of dead cells
Coagulative necrosis occur only in :
Solid organs except brain
Coagulative necrosis Example :
MI
How to determine necrotic myocardial cells :
Acidophilic , loss of nuclei and striations
How to get red of coagulatied necrotic cells :
Fragmentation and phagocytosis
Liquefaction necrosis is characterised by :
Softening of of the necrotic tissue
Liquefaction necrosis is found in :
- Brain infarction
- Abscess
Liquefaction necrosis in brain is due to :
Hydrolytic action of enzymes
The organelles involved in Liquefactive necrosis in abcsess :
Lysosomes of the inflammatory cells invading the necrotic tissue