Passage of an action potential along a myelinated axon

• In a myelinated axon, the fatty sheath of myelin around the axon acts as an electrical insulator, preventing action potentials from forming.
• At intervals of 1-3mm, there are breaks in the myelin insulation, known as nodes of Ranvier.
• Action potentials can occur at the nodes of Ranvier, allowing for localised circuits to arise at adjacent nodes. The electrical impulse can jump between nodes of Ranvier in a process known as saltatory conduction.
• Due to saltatory conduction, an action potential passes along a myelinated axon much faster than an unmyelinated one of the same diameter.