No. It does not. It can not. It neither affect the neurons also.
Myelin sheaths are located around the nerve cells. In central as well as peripheral nervous system.
Oligodendrocyte; processes of the oligodendrocytes form the myelin sheaths around the CNS nerve fibers
No, they form myelin sheaths on axons in the CNS while schwann cells form myelin sheaths in the PNS. Hope this answers your question.
MS
The interaction of the destruction of the myelin sheaths and remyelination is not yet fully understood. The lesions and scarring of the nerve tissue seem to mainly occur in the CNS, with the autoimmune process largely ignoring the peripheral nervous system.
Schwann cells in the peripheral nervous system form myelin sheaths around axons, which helps to speed up the transmission of nerve impulses. These myelin sheaths act as insulating layers that ensure efficient communication between neurons.
The main function of glial cells, specifically oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, is to provide insulation to neurons through the formation of myelin sheaths. These myelin sheaths wrap around the axons of neurons, which helps to increase the speed and efficiency of electrical signal conduction along the neuron.
myelin sheath
By being wrapped in myelin sheaths, produced by Schawann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.
Your question is not complete. There is not enough information. What are you referring to as "they". Some nerve fibers have thick myelin sheaths and some don't.
That is the correct spelling of "adrenoleukodystrophy" (also called Siemerling-Creutzfeldt Disease and adrenomyeloneuropathy) a disorder affecting myelin sheaths in the nervous system.
Schwann Cells make the myelin found in the (PNS) Peripheral Nervous System. It also helps speed up neurotransmissions. I hope this was helpful. for the central nervous system (brain & spinal cord) oligodendrocytes form the myelin.