What is the role of the myelin sheath in nerve cells?

The myelin sheath plays a crucial role in enhancing the speed of electrical impulses that travel along nerve cells. This sheath is a fatty layer that surrounds the axons of neurons, acting as an insulator. By insulating the axon, the myelin sheath allows electrical impulses to jump across the nodes of Ranvier, which are small gaps in the myelin sheath. This process, known as saltatory conduction, significantly increases the speed at which impulses are transmitted compared to unmyelinated axons, where impulses travel more slowly.

While protecting the neuron and providing nourishment are important aspects of neuronal health, these functions are primarily handled by other types of cells, such as glial cells. The production of neurotransmitters also falls outside the direct role of the myelin sheath; this process is typically carried out by the neuron itself. Therefore, the primary and defining function of the myelin sheath is to facilitate rapid communication within the nervous system by speeding up the electrical impulses.