Myelin is the insulation that forms around nerves with the purpose of acting as an electrically insulating layer. Created by glial support cells, myelin allows impulses to quickly travel through nerve cells, and consists of proteins whose function differs depending on where it is employed in the body. 

 If the myelin is damaged, these impulses slow down, leading to health conditions. The Central Nervous System (CNS) differs from the Peripheral Nervous System (PNS), and the ways that myelin is synthesized in each of these creates different complications. Demyelination occurs when the body attacks its own healthy myelin, eventually so badly that no further replacement of myelin is possible.