Ranvier was a French histologist and pathologist. He is credited with transforming histology from a descriptive discipline into an experimental science that could serve as a basis for physiological observations. He devoted most of his research to elaborating detailed nerve and skin structure. In 1878 he described constrictions seen in certain nerve fibers, now known as the nodes of Ranvier, where discontinuities occur in the nerve’s myelin sheath, and discovered nerve terminals between the epithelial cells of the tongue that are now known as Ranvier’s tactile disks.
Node of Ranvier
Node of Ranvier is a periodic gap in the insulating sheath (myelin) on the axon of cerain neurons that serves to facilitate the rapid conduction of nerve impulses. Myelin sheath acts as a high-resistance, low-capacitance electrical insulator. However, nodes of Ranvier interrupt the insulation at intervals, and this discontinuity enables impulses to jump from node to node in a process known as saltatory conduction. The action potential propagated by one node of Ranvier jumps to and is regenerated at the next node along the axon, thereby enabling the action potential to travel rapidly along the fibre.