The central nervous system (CNS) is the part of the nervous system that
integrates the information that it receives from, and coordinates the
activity of, all parts of the bodies of bilaterian animals-that is, all
multicellular animals except sponges and radially symmetric animals such
as jellyfish. It contains the majority of the nervous system and
consists of the brain and the spinal cord. Some classifications also
include the retina and the cranial nerves in the CNS. Together with the
peripheral nervous system, it has a fundamental role in the control of
behavior. The CNS is contained within the dorsal cavity, with the brain
in the cranial cavity and the spinal cord in the spinal cavity. In
vertebrates, the brain is protected by the skull, while the spinal cord
is protected by the vertebrae, and both are enclosed in the meninges.