Together, the brain and the spinal cord are called the central nervous system (CNS). Our brain controls how we think, feel, learn and move. It also controls other important things in the body without us being aware of it, such as breathing and heart rate. The bones of the skull protect the brain.
The spinal cord is a long bundle of nerves down the middle of the backbone (spine). It starts at the base of the brain and goes down to the small of the back. Messages between the brain and other parts of the body travel through the spinal cord. The bones of the backbone (vertebrae) protect the spinal cord.
The brain and spinal cord are also covered and protected by three layers of tissue (membranes) called the meninges. The area between two of these layers (the subarachnoid space) contains a liquid called cerebrospinal fluid (CSF). This makes a protective cushion for the brain. The liquid also circulates nutrients to the brain and removes waste products.