Multiple Sclerosis

MS is thought to be an autoimmune disease. The body’s own defense system attacks myelin, the fatty substance that surrounds and protects the nerve fibers of the brain, optic nerves, and spinal cord. The damaged myelin may form scar tissue (sclerosis). Sometimes the nerve fiber is also damaged. When any part of the myelin sheath or nerve fiber is damaged or destroyed, nerve impulses to and from the brain are distorted or interrupted.

Like insulation on electrical wire, myelin insures rapid transmission of nerve impulses from the brain to a body part and from the body to the brain to interpret sensations. When myelin is destroyed the messages are not transmitted effectively so movement is slow or uncoordinated and sensation is altered.

While at first there may be healing and return to normal function, later a scar (called a plaque) is formed which permanently interferes with nerve transmission and motor or sensory function. Damage to the myelin can occur at any time and affect any part of the brain or spinal cord.

Because there are multiple areas of scarring (sclerosis) the disease is called multiple sclerosis. Each person with MS will have a unique set of symptoms depending on where in the CNS the demyelination occurs.

Without myelin, signals transmitted through the central nervous system are slowed, garbled, or blocked and symptoms develop.

© Copyright the MS Society, Calgary Chapter.  All rights reserved.