Your myelin sheath isn’t one solid covering. It’s a lineup of individual sections of myelin, each separated from the next by a tiny gap — like the small amount of space you see between individual box cars on one long train. Each section of myelin is called an internode. Each gap in the myelin sheath — between internodes — is called the nodes of Ranvier. The nodes of Ranvier are rich in positive sodium ions. As the electrical signal or impulse travels along the axon, it jumps from one node to the next. When passing over the gap, the sodium ions recharge the electrical signal so it can continue in its travel without losing its charge or lessening in signal strength.