Myelin is a fatty substance that wraps around nerve fibers (axons) to insulate them and increase transmission speed of neural signals.
This is a long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells.
Schwann Cells: These cells produce myelin in peripheral nervous system (outside brain & spinal cord).
Multiple Sclerosis (MS): A disease where immune system attacks myelin sheath leading to communication problems between brain & rest body.