Necrosis

Necrosis NECROSIS 00:35 Severe/Persistent Ischemia K+ Ca2+ + Severe/Persistent Hypoxia Na Na+ ATP ATP Depletion k+ Na+-K+ ATPase pump stops Na+ Ca2+ In case of reversible injury K ATP was L, not completely depleted : Ca2t increase in LIGHT MICRDSCOPIC CHANGES Reversible injury is not significant Ca2+ Large amorphous densities in mitochondria Being a cofactor for enzymes. ACTIVATES ENZYMES ATPase Protease Phospholipase Endonuclease Chromatin damage Deplete ATP Plasma membrane damage Pyknosis Lysosomal membrane damage Karyorrexis Release hydrolytic enzyme Karyolysis Tissue damages ACUTE INFLAMMATION

Damaged proteins Eosinophil Karyolysis Basophilia ELECTRON MICROSCOPIC CHANGES Large flocculent amorphous density in mitochondria. Myelin figures : Laminated deposites of damaged phospholipids. Phospholipid on P. lipases. Phospholipid integrated Membranes Products LIGHT MICROSCOPIC CHANGES NECROSIS Tomb stone Coagulative Liquifactive even outline is Appearance 4 lost COAGULATIVE NECROSIS -PM of cell damaged but not dissolved completely because enzymes required for dissolution are inactivated by pit. - Cell outline is maintained for few days. - Complete dissolution occurs with reactivation of enzymes.

- Neutrophils seen indicating inflammation - Highly eosinophilic cytoplasm- - Seen in case of :- i. Ischemia ii. Thermal injury iii. Zerkers degeneration : Necrosis of Rectus abdominis musde in Typhoid Fever LIQUIFACTIVE NECROSIS - When plasma membrane is completely dissolved. - No outline of plasma membrane is seen. - Neutrophilic infilteration is seen. - Occurs in case of Ischemia to Brain & Spinal cord As these structures have myeline instead of collagen which doesn't provide support to plasma membrane. Coagulative necrosis + Bacterial infection Proteolytic enzymes of the bacteria may dissolve the outline. - Pus is liquified necrosed tissue + Neutrophil - Abscess : Localised collection of pus.