How does the ability of cells in the peripheral nervous system (PNS) to regenerate differ from that of cells in the central nervous system (CNS)?

Cells in the peripheral nervous system (PNS) can regenerate due to the presence of the neurolemma and Schwann cells, which promote healing. In contrast, cells in the central nervous system (CNS) lack this regenerative capability; once they are destroyed, they cannot be replaced.

The ability of cells in the PNS to regenerate is facilitated by the neurolemma, which surrounds the axons and aids in the healing process. Schwann cells, which form myelin sheaths around PNS axons, also contribute to regeneration. Conversely, CNS cells do not have a similar regenerative ability; once CNS neurons are damaged or destroyed, they cannot be replaced, although other brain cells may compensate for lost functions.