Nodes of Ranvier are the 1-micrometer gaps formed along the length of the myelin-wrapped axons of the nerve cells. The nodes allow the nerve impulses to jump from one node to the next. This is called saltatory conduction. Neurons axons are encased in a sheath of many-layered fatty coating called myelin, which is produced by the Schwann cells. This axonal membrane is uninsulated at nodes of Ranvier and therefore capable of generating electrical activity.