Multiple sclerosis, also known as MS, is a chronic disease that attacks the central nervous system, i.e. the brain, spinal cord and optic nerves. In severe cases the patient becomes paralyzed and/or blind, while in milder cases there may be numbness in the limbs. With MS the central nervous system (CNS) is attacked by the person's own immune system. That is why MS is known as an auto-immune disease. Nerve fibers are surrounded by myelin, which protects them. Myelin also helps conduct electrical signals (impulses) - i.e. myelin facilitates a good flow of electricity along the nervous system from the brain. Myelin regulates a key protein involved in sending long-distant signals.
The myelin of a patient with MS disappears in multiple areas. This leaves a scar (sclerosis).Multiple Sclerosis means "Scar Tissue in Multiple Areas". The areas where there is either not enough or no myelin are called plaques or lesions. As the lesions get worse the nerve fiber can break or become damaged. When a nerve fiber has less myelin the electrical impulses received from the brain do not flow smoothly to the target nerve - when there is no myelin the nerve fibers cannot conduct the electrical impulses at all. The electrical impulses are instructions from the brain to carry out actions, such as to move a muscle. With MS, you cannot get your body to do what your brain wants it to do.