Apoptosis:
- Programme cell death.
- Pathway of cell death in which cells activate enzymes that degrade their own nuclear DNA and nuclear and cytoplasmic proteins.
- Fragments of apoptotic cell then break off; giving the appearance that is responsible for name “apoptosis- falling off”.
- Plasma membrane remains intact but membrane is altered in such a way that cell and its fragments becomes target for phagocytes. The dead cells and its fragments are rapidly cleared before cellular contents leaks out. So, apoptotic cell death doesn’t elicit an inflammatory reaction in the host.
- Both intrinsic and extrinsic pathways play role.
- It is different from necrosis, although it shares some features.
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Necrosis |
Apoptosis |
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It involves masses of cell that are passive just gets killed by external stimuli. |
It involves small cluster of cell that are active. |
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Hypoxia, toxins plays role in necrosis. |
Both physiological and pathological factors plays role. |
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Necrotic cell swells up. |
Cytoplasm condensed, cell shrinks down, genetic material undergoes fragmentation. |
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Heavy disruption of cell membrane. |
Cell membrane mechanism is altered only. |
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Intracellular enzymes comes out and damage surrounding tissues and inflammatory process starts. |
No inflammatory reactions. Phagocytosis of apoptotic bodies. |
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Random, diffuse breakdown of DNA. |
Inter-nucleosomal breakdown of DNA. |
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Cell death is through ATP depletion, membrane injury. |
Cell death is through gene activation, endonucleases, proteases. |