What is the central nervous system (CNS)?

The spinal cord and the brain together make up the central nervous system (CNS).

The CNS controls most functions of the body, but is not the only nervous system in the body. The peripheral nervous system (PNS) includes the nerves that project to the limbs, heart, skin, and other organs outside the brain. The PNS controls the somatic nervous system, which regulates muscle movements and the response to sensations of touch and pain, and the autonomic nervous system, which provides nerve input to the internal organs and generates automatic reflex responses. The autonomic nervous system is divided into the sympathetic nervous system, which mobilizes organs and their functions during times of stress and arousal; and the parasympathetic nervous system, which conserves energy and resources during times of rest and relaxation.

The spinal cord acts as the primary information pathway between the brain and all the other nervous systems of the body. It receives sensory information from the skin, joints, and muscles of the trunk, arms, and legs, which it then relays upward to the brain. It carries messages downward from the brain to the PNS. It contains motor neurons, which direct voluntary movements and adjust reflex movements. Due to the central role it plays in coordinating muscle movements and interpreting sensory input, any kind of injury to the spinal cord can cause significant problems throughout the body.

This answer is based on source information from the National Institute of Neurological Disorders and Stroke.

The central nervous system (CNS) is made up of the brain and spinal cord. The CNS contains nerves, which are like wires inside the body that send and receive messages. This is how the CNS does its job. The CNS works hard to help people do important things like thinking, feeling, seeing, hearing, talking and moving. Messengers carry the messages that travel from the brain through the spinal cord, telling the body what to do.

Dr. Asma Taha
Child Neurologist

The central nervous system (CNS) is one of the two parts of the nervous system. The second part is the peripheral nervous system (PNS). The CNS consists of the brain and the spinal cord. The PNS includes all of the nerves that are located outside of the brain and spinal cord. The PNS is responsible for carrying information in form of different type of stimulus to and from the CNS. 

The brain contains three main areas: the cerebrum, the cerebellum, and the medulla oblongata. The cerebrum is responsible for conscious functions, while the cerebellum and the medulla oblongata control the unconscious functions such as breathing, heart rate, swallowing and gagging reflexes.

The spinal cord is a cylindrical shaped bundle of nerve fibers that is connected to the brain. The spinal cord is protected by the vertebra, meninges, and cerebrospinal fluid. The spinal cord extends from the foramen magnum and the first cervical vertebra to the second lumber vertebra in adults and the third lumbar vertebra in children. The spinal cord nerves transmit information from body organs and external stimuli to the brain and send information from the brain to other areas of the body. These nerves are grouped in bundles of fibers that travel in two pathways. Ascending nerve tracts carry sensory information from the body to the brain while the descending nerve tracts send information pertaining to motor function from the brain to the rest of the body.

Continue Learning about Healthy Nervous System

How can the nervous system help people get stronger?
Dr. Mike Clark, DPTDr. Mike Clark, DPT
The nervous system is an important facet of an exercise plan. In the beginning of an exercise pl...
More Answers
What sets humans apart from other species?
Discovery HealthDiscovery Health
The cerebral cortex is what separates human beings from other species. It regulates language and int...
More Answers
Is there a link between insanity and genius?
Discovery HealthDiscovery Health
Obviously, we cannot perform psychological exams on people who died ages ago, but that has not stopp...
More Answers
What controls beta-amyloid?
Dr. Michael Roizen, MDDr. Michael Roizen, MD
In general, genes control how much beta-amyloid you have in your brain. Some branches may be knockin...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.