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IB. Neurons - pathological changes

Neurons - Pathological reactions (cont)

c. Axonal reaction / central chromatolysis / Wallerian degeneration: When the axon of a neuron is cut or damaged, the axon and its myelin sheath undergo degeneration distal to the lesion (Wallerian degeneration). The sequence of events that takes place in the cell body is known as central chromatolysis or axonal reaction.

  • The cell body swells.
  • The Nissl bodies disperse and move peripherally.
  • The nucleus is displaced peripherally in the cell. 
  • This is a reparative process associated with increased protein synthesis to facilitate axon regeneration.


The cell on the left is undergoing chromatolysis.
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