Nerve cells. Computer artwork of two nerve cells or neurons. Neurons are responsible for passing information around the central nervous system (CNS) and from the CNS to the rest of the body. Each nerve cell comprises a body surrounded by numerous extensions called dendrites. Dendrites collect information from other nerve cells or from sensory cells. Each neuron also has one process called an axon, which passes information to other nerve cells, or to effector cells such as muscle fibres. The axons appear segmented as they are surrounded by a myelin sheath, which contains gaps, called nodes of Ranvier. The myelin insulates the axon, allowing signals to be transmitted more quickly.