Regeneration and Repair
Plasticity: the capability to change based upon experience. Individual neurons can change, sprouting new dendrites, synthesis of new proteins, and changes in synaptic contacts with other neurons.
e.g. dendrite and protein synthesis, synaptic contacts
Regeneration: the capability to replicate or repair themselves. In the PNS, damaged dendrites and myelinated axons may be repaired if the cell body remains intact and if the Schwann cells that produce myelination remain active. In the CNS, there is little to no regeneration.
Neurogenesis in the CNS: the birth of new neurons from undifferentiated stem cells.
The process of neurogenesis is very limited in humans. It occurs only in hippocampus , the region of the brain responsible for learning. The lack of regeneration and repair in the CNS is most likely due to inhibiting activity from neuroglia, as well as an absence of growth-stimulating cues. Neurogenesis can be stimulated by EGF (epidermal growth factor), which is not found in mature CNS tissue.
Damage and Repair in the PNS
Unlike the CNS, repair in the PNS is possible if :
cell bodies are intact
Schwann cells are functional
scar tissue formation is controlled
166
Made with FlippingBook Publishing Software