The brain sends messages into the rest of the body. These messages are transmitted through the nervous system. 

When a brain sends a message into the body, it first travels through the spinal cord. It is protected by the vertebrae of the backbone and it is connected to a network of nerves that covers every place in the body.

By travelling through the nervous system, the messages are quickly transmitted into various parts of the body, such as hormone-producing glands and muscles.

The messages travel through the nervous system in the form of electric impulses. 

Information is also transmitted from other parts of the body back into the brain. The most important sources of information are the body's receptor cells. Receptor cells are specialized in sensing various kinds of information.

For example, the receptor cells in your eye help to sense visual information from the world around you, whereas the receptor cells in your skin help to sense whether not it is cold or warm outside. 

The information gathered by the receptor cells travels back to the brain through the nervous system.