Myelin acts as a kind of conductive blanket around nerves, helping nerve impulses or messages travel faster and more effectively. Often the role of myelin is to speed up nerve cell communications from the brain and spinal cord, for example, to other parts of the body. In anatomy, myelin is described as a sheath or layer, and it insulates nerves so impulses can transmit uninterrupted to signal body functions such as movement and speech. When myelin is damaged or is degenerating, diseases such as multiple sclerosis develop and often, debilitation results.
Looking at the role of myelin in the body is similar to inspecting an electrical cord or even a water hose. When electricity flows through an intact cord, the cord itself helps move the energy along its path from the power source to the site needing electricity, for example, a circulating fan. Electrical impulses go directly from source to object, but if the cord is damaged, electricity shorts out and power output stops or weakens or overheating occurs and the fan won't work. A water hose operates in a similar way, with a source spigot and a hose opening where the water sprays out. Cracks in the hose cause water to splutter out or lose direction outward so it doesn't have a direct path to power out of the hose as it should.
In very simple terms, the role of myelin is to keep the nerve impulses on course to their destinations in the body so the body can work. It is like the outer layer of a hose or a cord in a sense but it facilitates movements and communications among neurons, cells, nerves, and synapses. When the insulated sheath is damaged or impaired, the role of myelin is compromised and even the most ordinary bodily functions such as talking, walking, and completing a thought degenerate and sometimes fail altogether. Nerve impulses cannot zip and shoot through on their way to targets, they stutter and slow instead.
Diseases associated with the loss of myelin, or demyelination, are generally in the group called neurodegenerative because they impair neurological processes. Often, the central nervous system loses its ability to communicate with the rest of the body. Leukodystrophies and multiple sclerosis are inherited and acquired diseases directly connected to the role of myelin, both resulting in loss of neurological, muscular, and often whole body functioning. Scientific research and medical experimentation in repairing myelin is ongoing.