What is saltatory conduction?

·   Myelin sheath is an insulating layer of fatty material, composed of Schwann cells wrapped tightly around the neurone.·   Sodium and potassium ions cannot diffuse through this fatty layer.·   In between the Schwann cells are small gaps- the nodes of Ranvier.·  Therefore, the ionic movements that create an action potential cannot occur over much of the length of the neurone: they occur only at the nodes of Ranvier.·   In myelinated neurones the local currents are therefore elongated and sodium ions diffuse along the neurone from one node of Ranvier to the next.· This means that the action potential appears to jump from one node to the next.·  This is called saltatory conduction.