What is the time difference in myelinated vs. unmyelinated axons? Solution The gap junctions found at regular intervals in the myelin sheath are called as Nodes of Ranveir. Myelin sheath does not allow the exchange of ions through it and exchange of ions occurs at Nodes of Ranveir only. Myelin sheath helps in the faster conduction of impulses through the axons by saltatory conduction (impulses jump from one node to another). Thus, the impulses are conducted faster in myelinated neurons (glial cells insulate the neurons with myelin sheath) than non-myelinated neurons. In non myelinated neurons, the ions move through the axon length, so the conduction is slower..