What is the purpose of the myelin sheath?

The myelin sheath plays a crucial role in the functioning of the nervous system by insulating nerve fibers. This insulation helps to speed up signal transmission along the axons of neurons, allowing electrical impulses to travel more quickly and efficiently. The myelin sheath is composed of layers of glial cell membranes that wrap around the axon, creating segments that are interrupted by nodes of Ranvier. These nodes allow for saltatory conduction, where the nerve impulses jump from one node to the next, significantly increasing the speed at which signals are transmitted compared to unmyelinated fibers. This is essential for the rapid communication necessary for muscle movement, reflexes, and various bodily functions.

While other options outline important functions within biological systems, they do not pertain specifically to the role of the myelin sheath in signal transmission.