Human nervous system with a female skeleton, artwork. The human nervous system consists of the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS comprises the brain (grey, top) and the spinal cord (yellow, down centre). The PNS consists of nerves (yellow) branching off from the spinal cord to all areas of the body. In humans, the nervous system contains billions of nerve cells that transmit electrical impulses to control and co-ordinate the many other systems that keep the body functioning. Some neural functions are under conscious control, while others function autonomously at a subconscious level.