The brain is the control centre for the rest of the body. All parts of the brain, spinal cord, and nerves pass messages using electrical current. Most automatic actions like breathing are controlled in the lower brain at the back and bottom of the skull. Decision making, movement, sensation, and many other functions are controlled by different parts in the larger, upper part of the brain.
There are spaces called ventricles in the middle of the brain that hold cerebral spinal fluid (CSF) that acts as a cushion for the brain. There are also important nerves called cranial nerves that link directly from the brain to specific areas of the body.
The spinal cord is the main link connecting the brain and the body. It is protected inside a series of spinal bones called vertebrae. The vertebrae are stacked on top of each other with padding in between. Each pad is called a ‘disc’.
Nerves to and from the rest of the body branch off of the spinal cord all the way down the back. These nerves branch off further, providing the signals needed to make muscles move and feel sensations like pressure, heat, and pain.