Multiple Sclerosis (MS) is an inflammatory disease of the Central Nervous System (CNS). It is also believed to be an autoimmune disease; a disease where the body’s immune system attacks the myelin (see below). It is among the most common neurological diseases causing disability in young adults in North America and Europe. MS primarily results from the destruction of myelin. The myelin is made by oligodendrocytes (an important cell type of the CNS) and serves to insulate nerve fibers, helping them to conduct electrical impulses more efficiently. - The nerve cells or neurons are the main component of the gray matter.
- Each nerve cell has an axon (the nerve fiber) which conducts nerve impulses to and from the brain. The areas where the inflammation and demyelination occur are called plaques.
- Plaques may be located in the optic nerves, cerebral hemispheres, brainstem and spinal cord.
- Axons (or nerve fibers) are relatively spared in demyelination, compared to the myelin itself.
- However recent studies have shown that there is nerve fiber destruction as well as myelin destruction.
- The axonal loss is probably an important determinant of permanent, irreversible neurological impairment in MS.
Visit MUSC's Health Information Library for more information about multiple sclerosis. | 
