Describe how an action potential is transmitted down the axon of a myelinated neurone

Depolarisation of the membrane in a myelinated neurone occurs in gaps between the schwann cells of the myelin sheath known as nodes of Ranvier. During depolarisation of the membrane at a node there is an influx of sodium ions through voltage-gated sodium ion channels, is creates a region of high sodium ion concentration in the axon of the neurone resulting in the sideways diffusion of these ions down the neurone. This is known as a 'local current', since it involves the movement of charged particles (the sodium ions). This local current spans from one node to the next and triggers an action potential in the next node beacause the sodium ions depolarise the membrane enough to reach the threshold value. This process is known as Saltatory conduction, in which the action potanetial 'jumps' from one node to the next along the axon of a myelinated neurone.