Neuroanatomy, Nodes of Ranvier

Myelin sheaths insulate the axons of nerves. These sheaths are a lipid-rich extension of the plasma membrane produced in the peripheral nervous system (PNS) by Schwann cells and by oligodendrocytes in the central nervous system (CNS). The myelin sheath is regularly interrupted along the length of the axon by specialized regions called the nodes of Ranvier, which are necessary for the propagation of an action potential along the axon. The nodes of Ranvier are essential in the speed and timing of delivery of impulses from one neuron to another, and changes in size or function have the potential to jeopardize the effectiveness of a neuron, contributing to the development of neurological disorders.