Introduction

Abstract

In 1854 Virchow described sheaths around the nerve fibers in the central nervous system and suggested the name myelin. It is not certain when Schwann (1810–1882) described the cells which have since been named after him that supply the myelin sheaths around the peripheral nerve fiber (1839?). In 1878, Ranvier described the nodes since named after him in Leçons sur l’histologie du système nerveux. He believed that the nodes prevented the essentially liquid myelin from flowing to the bottom of the nerve fiber (axon). But despite this conviction, he showed considerable insight into the functional role of the myelin sheath, both as an insulator and as a facilitatory agent in CNS functions. It was not until 1960–1961, that the role of the oligodendrocyte in the formation of myelin in the central nervous system became clear, due to the work of Bunge.