What is the primary function of myelin sheaths formed by Schwann cells?

The primary function of myelin sheaths formed by Schwann cells is to insulate axons. Myelin is a fatty substance that surrounds the axons of many neurons in the peripheral nervous system, created by Schwann cells. This insulation is critical for the efficient and rapid transmission of electrical impulses along the axon. It helps to prevent the loss of electrical signals, allowing for faster conduction of action potentials through a process known as saltatory conduction. By providing insulation, myelin sheaths enable nerve impulses to jump from one node of Ranvier to the next, significantly increasing the speed of communication between nerve cells.

While protecting nerve cells is an important aspect of myelin and Schwann cells, the primary role is indeed focused on insulation and speeding up signal transmission.