Nerve cell. Light micrograph of a nerve cell, or neuron. Neurons are responsible for passing information around the central nervous system (CNS) and from the CNS to the rest of the body. The cell comprises a body (oval) surrounded by numerous extensions. There are two types of extensions, dendrites and axons. The dendrites collect information from other nerve cells. The information is passed to the cell body, where it is interpreted. The axon (running down centre), which is wrapped in a sheath of the protective substance myelin, then sends out a signal based on the input from the dendrites.