Neuron (nerve cell) axon anatomy, illustration. Neurons are responsible for passing information around the central nervous system (CNS) and from the CNS to the rest of the body. Each neuron has one axon, an extension through which information passes outwards to other cells. The axon appears segmented as it is surrounded by a myelin sheath that contains gaps, called nodes of Ranvier. The myelin insulates the axon, allowing signals to be transmitted more quickly. It is formed when Schwann cells wrap around the fibre, depositing layers of myelin between each coil. Microtubules and microfilaments are part of the cytoskeleton.