This acrylic painting (18×24″) shows neurons with a focus on the axons (brown) and glia. These glia are called oligodendrocytes and their main role is to support neurons, at least that is the classical thinking.
Neurons send electrical signals through their axons. The speed of the electrical signal is determined by the myelin sheath which is made from a glial cell called an oligodendrocytes (blue). The oligodendrocytes wrap their processes around the axons and can do this to up to 50 axons.
The myelin is considered insulation. Signals are transmitted between myelin, with the signal jumping between these nodes (nodes of Ranvier). Yes nodes of Ranvier are named after the guy who discovered them.
Multiple sclerosis is a central nervous system disease that Of the nervous system associated with inflammation and damage to the oligodendrocytes.