Action potential propagation and synchronisation in myelinated axons
Fig 1
Action potential propagation in a myelinated axon.
A: The axon is made of myelinated segments (internodes), with the nodes of Ranvier forming periodic gaps in the myelin sheath. B: The nodes of Ranvier constitute active sites at which threshold-triggered ion channel currents are released. C: The currents entering nearby nodes of Ranvier determine the membrane potential at each node, thus forming an action potential. D: The velocity of an action potential is determined by the distance L between two consecutive nodes, and the time difference tsp it takes to reach a given threshold value.