The nervous system includes the brain, the spinal cord, and all the nerves in the body. Nerves carry information through the spinal cord to the brain about what is happening inside and outside of the body. The brain processes the information and sends messages back through the nerves that control how muscles and other organs respond.

The nervous system is divided into two parts. The brain and the spinal cord are called the central nervous system. The nerve cells that connect the brain and the spinal cord to other parts of the body are called the peripheral nervous system. The nervous system controls:

• Sight, hearing, taste, smell, and feeling (sensation).
• Movements you choose to make (voluntary) and those that happen without your thinking about them (involuntary), like breathing. The nervous system controls most body systems and processes like blood flow and digestion too.
• The ability to think. The nervous system allows a person to be conscious, to have thoughts and memories, and to use language.