Anatomically ...

The nervous system consists of two major components:

  1. The Central Nervous System (CNS), composed of the brain and spinal cord. Its major functions are to integrate sensory information, and to initiate and co-ordinate efferent responses. Find out more about the CNS
  2. The Peripheral Nervous System (PNS), composed of all the nervous tissue outside the CNS. The PNS is represented by cranial nerves from the brain, spinal nerves from the spinal cord, and nodules known as ganglia, that contain the neuronal cell bodies. Find out more about the PNS

Functionally ...

The nervous system consists of:

  • the somatic nervous system, which controls voluntary functions
  • the autonomic nervous system, which controls involuntary activities.

Despite these complexities, the nervous system, throughout, consists of two main cell types: neurons and supporting cells.