The role of the myelin sheath in nerve conduction is to insulate nerve fibers and speed up the transmission of electrical signals along neurons. This protective covering is composed of multiple layers of lipid-rich membranes produced by glial cells. By preventing electrical leakage, the myelin sheath allows for faster conduction through a process called saltatory conduction, where signals jump between nodes of Ranvier. Efficient nerve conduction is vital for the proper functioning of the nervous system, facilitating rapid communication between different parts of the body and enabling responses to stimuli.