1 Apoptosis Vs Necrosis PDF

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Summary

Apoptosis Necrosis...

Description

NECROSIS

APOPTOSIS

 Large number of cells die

 Cell shrinks and engulfed by phagocyte  Regulated form of cell death which may be both physiological and pathological

 ⬆eosinophilic staining – denatured proteins and loss of RNA  Vacuolation – digested cytoplasmic organelles  ER and Mt swelling  Discontinuous membranes

   

CAUSES

Coagulative - Denaturation of proteins - Cells dead - Tissue architecture preserved Liquefactive - Enzymatic digestion of ALL macromolecules - Cells digested - No tissue structure - Inflammatory response Caseous - Tissue architecture obliterated - Fragmented lysed cells with amorphous granular appearance Fat

 Ischemia  Bacterial and fungal infection; ischemia  Mycobacterium tuberculosis  Acute pancreatitis  Leakage of fibrin and inflammatory cells  Lower limb has lost its blood supply

- Focal areas of fat destruction - Enzymes liquify membranes of fat cells - Release fatty acids ➙ mix with Ca ➙ white lesions Fibrinoid - Deposition of immune complexes in blood vessels

Intensely eosinophilic cytoplasm Nuclear chromatin condensed and fragmented Formation of apoptotic bodies NO inflammatory response

Physiological Embryogenesis Involution Cell loss in proliferating cell population Elimination of cells that have reached their used by date Self-reactive T-lymphocytes Pathological -

DNA damage Accumulation of misfolded protein Cell death in infection Pathologic atrophy

Intrinsic Pathway Growth factor withdrawal DNA damage Protein misfolding There is a balance b|w pro- and anti-apoptotic members of the Bcl-2 family Extrinsic Pathway Cytotoxic T-cell recognition of infected cells Elimination of lymphocytes that fight self-cells

CAUSES  Radiation, cytotoxic drugs, extreme temp., hypoxia, ROS  Mutations, ROS, degeneration in CNS



Viral infection, host eliminating infected cells

Gangrenous - Coagulative/liquidative - Lower limb Cell size

 Enlarged – swollen

 Reduced

Nucleus

Breakdown of DNA and chromatin  Pyknosis: nuclear shrinkage and ⬆ basophilia (condensed)  Karyorrhexia: nuclear fragmentation Karyolysis: ⬇ basophilia from DNA breakdown 

Plasma membrane

 disrupted

 intact BUT altered

Cellular contents

 enzymatic digestion  leakage

 intact  apoptotic bodies

Inflammati on

Y

N

 Karyorrhexia

Necroptosis Hybrid form of cell death - Features of necrosis o Loss of ATP o Cell and organelle swelling o Generation of ROS o Rupture of cell membrane - Features of apoptosis o Genetically programmed signal transduction events - Different o Initiated by ligation of receptor with ligand o Caspase independent...