Node of Ranvier is defined as:

1. short unmyelinated section of Axon between segments of myelin

2. regular gaps along the Axon where the myelin is interrupted

3. gaps that oc cur at regular intervals in the myelin sheath of medullated nerve fibres, between adjacent Schwann cells

4. any of the constrictions along the myelin sheath that surrounds an axon of a nerve cell: nodes are formed where two Schwann cells meet and are essential to the proper transmission of nerve impulses

The key functions of Nodes of Ranvier include:

1. Allowing nutrients and waste products to enter/leave the neurone.

2. Allowing nerve impulses to move along the neurone through a process of de-polarisation and re-polarisation of the nerve membrane.

Node of Ranvier is named after Louis-Antoine Ranvier Ranvier (1835-1922), a French histologist, pathologist and anatomist.