Saturday, May 9, 2009

Saltatory Conduction

Saltatory conduction is the means by which a nerve impulse is conducted rapidly through myelinated axons. The nerve signal appears to leap from one node of Ranvier to the next, rather than traveling the entire length of the axon. AS the cytoplasm of the axon is electrically conductive, depolarization at one node of Ranvier is sufficient to elevate the voltage at a neighboring node to the threshold for action potential initiation. Thus in myelinated axons, action potentials do not propagate as waves, but recur at successive nodes and in effect "hop" along the axon, by which process they travel faster than they would otherwise.