As you read this, electrochemical signals are racing along 30,000 miles of nerve cells (neurons) throughout your brain and body. This incredibly complex network, known as the nervous system, controls all of your conscious and unconscious actions by sending messages between the brain, spinal cord, and nerves. At the same time, it receives and processes information from inside and outside your body (through your senses). It controls the activities of your muscles and organs, as well as your thoughts and emotions. There are two broad divisions of the nervous system: the central nervous system is made up of the brain and the spinal cord. All the other nerve cells throughout your body make up the peripheral nervous system which consists of all the other nerve cells, including sensory nerves. It sends signals to and from different parts of the body. For example, it relays signals from your sensory organs to the brain and controls voluntary muscle movement like walking. It also controls many of the functions of your organs, such as the heart, stomach, and lungs. |
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