Example of a rough draft multiple sclerosis
As the disease progresses, the outermost layer of the brain, called the cerebral cortex, shrinks in a process known as cortical atrophy. MS also damages the nerve cell bodies, which are found in the brain's gray matter, as well as the axons themselves in the brain, spinal cord, and optic nerves that transmit visual information from the eye to the brain. MS attacks axons in the central nervous system protected by myelin, which are commonly called white matter. The disease is rarely fatal and most people with MS have a normal life expectancy. Most people with MS, however, will have short periods of symptoms followed by long stretches of relative quiescence (inactivity or dormancy), with partial or full recovery. A small number of people with MS will have a mild course with little to no disability, whereas others will have a steadily worsening disease that leads to increased disability over time. MS is a chronic disease that affects people differently.
Myelin is a substance that makes up the protective sheath (myelin sheath) that coats nerve fibers (axons). In MS, the immune system cells that normally protect us from viruses, bacteria, and unhealthy cells mistakenly attack myelin in the central nervous system (brain, optic nerves, and spinal cord). Multiple sclerosis (MS) is the most common disabling neurological disease of young adults with symptom onset generally occurring between the ages of 20 to 40 years.