The influx of sodium ions via voltage-gated channels is only possible at these nodes and therefore the nerve impulse is able to effectively 'jump' from node to node. This type of impulse propogation is called '''saltatory conduction'''. Myelination of axons in mammals means that the nervous system can sustain a large number of high velocity axons within a relatively small space. | The influx of sodium ions via voltage-gated channels is only possible at these nodes and therefore the nerve impulse is able to effectively 'jump' from node to node. This type of impulse propogation is called '''saltatory conduction'''. Myelination of axons in mammals means that the nervous system can sustain a large number of high velocity axons within a relatively small space. |