The gaps occurring between the glial-cell wrappers that form the myelin sheath surrounding many kinds of axons. The nodes are crucial to the rapidity at which neural impulses travel along myelinated axons.

Small gaps of exposed axon, between the segments of myelin sheath, where action potentials are transmitted. go to glossary index

are the gaps in the myelin sheath where the axolemma is directly exposed to tissue fluid. They contain ion channels and are responsible for propagating the action potential down the axon by saltatory conduction. They are also the site of origin for axon collaterals