What constitutes the central and peripheral nervous systems? How are the components of central nervous system protected?

The central nervous system is composed of the brain and the spinal cord. The peripheral nervous system is composed of cranial nerves arising from the brain and spinal nerves arising from the spinal cord.

Brain is a most important part of the body which needs to be carefully protected. Brain is located inside a bony box called skull. It is covered on the outside by three membranes called meninges. The cerebrospinal fluid files the space between these membranes and provides a cushion against mechanical shocks. Spinal cord gets protection by the vertebral column or backbone. Like the brain, it is also protected by three meninges and cerebrospinal fluid.