The nervous system is responsible for the body's muscle movement, coordination and control. It is divided into the central nervous system and the peripheral nervous system. The central nervous system is composed of the brain and the spinal cord. The brain is the major control center. It gives us the power to think, move, write, solve problems, and imagine. It interprets all the information sent to it from outside the body, and it controls our body temperature, heart rate, and breathing. The spinal cord is a bundle of nerve fibers that runs along the back and connects the brain to all of the other nerves in the body. These nerves that extend throughout the body are called the peripheral nervous system. They transfer messages to and from the brain via the spinal cord.