What is the function of the myelin sheath?

The myelin sheath plays a critical role in the functioning of neurons by insulating axons, which aids in the efficient transmission of electrical signals. This insulation reduces the leakage of ions across the axonal membrane, allowing for the electrical impulses, or action potentials, to travel more quickly and effectively along the axon. This process is known as saltatory conduction, where the action potential jumps from one node of Ranvier (gaps in the myelin sheath) to the next, significantly speeding up signal transmission compared to unmyelinated axons.

The myelin sheath is composed of glial cells, such as oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, which wrap around the axon to form this crucial insulating layer. The increased speed of signal transmission facilitated by the myelin sheath is essential for the rapid communication necessary for proper functioning of the nervous system, particularly in complex tasks like muscle movement and the coordination of various bodily functions.