Multiple sclerosis, or MS, is a disease of the central nervous system. Your central nervous system (CNS) includes your brain and spinal cord, which contains special kinds of cells called neurons that are designed to send signals throughout your body.1 These signals pass through nerve fibres called axons, which are protected by an insulating sheath composed of myelin. These signals are responsible for many functions, including balance, physical coordination, eyesight, and memory.2
MS is sometimes called an autoimmune disease. That's because in MS, the immune system mistakes the body's own tissue as "intruders," and turns against itself.3 These attacks damage the protective myelin coating around your axons, and can create patches of scar tissue called sclerosis, or lesions. In fact, the name multiple sclerosis actually means "many scars." 2
How MS affects the CNS
Normal healthy neuron
Nerve signals quickly pass down the axon with its protective myelin coat.
Myelin damage disrupts messages travelling along nerve fibres–messages may slow down, become distorted, short circuit or not get through at all–resulting in symptoms of MS. These symptoms can vary depending upon where the interruptions take place. Sometimes these symptoms come and go, while other times they can last longer or even be permanent.2