When neurons cannot undergo cell division then, how do nerves regenerate?
Nerves in the central nervous system do not regenerate. If the axon of a nerve in the central nervous system becomes severed it never grows back. In the peripheral nervous system however, schwann cells, which form the myelin sheath around axons in the PNS will form a kind of tunnel for a severed axon to regrow through.
The reason CNS does not regrow is that the oligodendrocytes release a growth inhibiting factor as well as Astrocytes cause scarring much too quickly. In the PNS the schwann cells form this tunnel and the axoplasm is continually pushed down the axon and it continues to follow the tunnel until it reaches its target of innervation. To do this it must go about 1-4mm a day otherwise the target may atrophy due to lack of innervation.
But still the question remains same how do these axons grow in those tunnels ?
