The basic components of central nervous system are the brain and the spinal cord. All the nervous activities are incorporated by the central nervous system.
Brain: The brain is a complex organ situated in the skull/cranium. Cranium is a bony structure to protect the skull. The average weight of the brain is about1400g. There is no lymphatic drainage to the brain.
Spinal cord: Spinal cord is the continuation of the brain. Similar to the brain the spinal cord is also protected by a bony structure called as the vertebral column or the back bone.