what direction does a nerve impulse travel
Saltatory Conduction. As in un-myelinated axons, the first action potential in myelinated axons takes place at the initial segment of an axon and is generated by a threshold stimulus from the dendrites and cell body. Subsequent action potentials occur at the nodes of Ranvier, where the Na+ voltage-gated channels are located. Therefore, when nerve impulses travel down a myelinated axon, they appear to jump from node to node - in a process called saltatory conduction. Each nodal action potential is triggered by a threshold stimulus created by passive current from the previous node.