Due to the myelination of neurones within mammalian nervous systems, action potentials may only occur at the Nodes of Ranvier. Myelin is made up of insulating cells which means depolarisation cannot occur in myelinated regions. Between these cells however, there are gaps known as the Nodes of Ranvier which are unmyelinated. As depolarisation cannot occur at the cells making up the myelin sheath, the wave of depolarisation can only occur at the Nodes of Ranvier. Thus, action potentials appear to jump from node to node when travelling down an axon.This speeds up the transmisson of action potentials massively.
- ↑ Alberts, B (2008). Molecular Biology of the Cell. New York: Garland Science. 680