What is the primary function of the myelin sheath in neurons?

The primary function of the myelin sheath in neurons is to increase the speed of nerve impulse transmission. Myelin is a fatty substance that wraps around the axons of neurons, creating an insulating layer. This insulation allows electrical impulses, known as action potentials, to travel much more quickly along the axon by enabling a process called saltatory conduction. In this process, the impulse jumps from one node of Ranvier (gaps in the myelin sheath) to the next, significantly enhancing the speed of communication between neurons.

This rapid transmission is crucial for efficient nervous system function, as it allows for quick reflexes and timely communication throughout the body. Myelin sheath presence is particularly important in larger diameter axons where fast transmission is required, such as in motor neurons and sensory neurons involved in rapidly relaying information.