Nervous System

Your nervous system plays a role in everything you do. The three main parts of your nervous system are your brain, spinal cord and nerves. It helps you move, think and feel. It even regulates the things you do but don’t think about like digestion. It contains the central nervous system and the peripheral nervous system.


The nervous system in a body, with the central system and peripheral nervous system.
Your nervous system contains your brain, spinal cord and nerves.

What is the nervous system?

Your nervous system is your body’s command center. It’s made up of your brain, spinal cord and nerves. Your nervous system works by sending messages, or electrical signals, between your brain and all the other parts of your body. These signals tell you to breathe, move, speak and see, for example. Your nervous system keeps track of what’s going on inside and outside of your body and decides how to respond to any situation you’re in.

Your nervous system regulates complicated processes like thoughts and memory. It also plays an essential role in the things your body does without thinking, like blushing, sweating and blinking.


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What does the nervous system do?

Your nervous system’s main function is to send messages from various parts of your body to your brain, and from your brain back out to your body to tell your body what to do. These messages regulate your:

  • Thoughts, memory, learning and feelings.
  • Movements (balance and coordination).
  • Senses (how your brain interprets what you see, hear, taste, touch and feel).
  • Wound healing.
  • Sleep.
  • Heartbeat and breathing patterns.
  • Response to stressful situations, including sweat production.
  • Digestion.
  • Body processes, such as puberty and aging.

How does the nervous system work?

Your nervous system uses nerve cells called neurons to send signals, or messages, all over your body. These electrical signals travel among your brain, skin, organs, glands and muscles.

The messages help you move your limbs and feel sensations, like pain. Your eyes, ears, tongue, nose and the nerves all over your body take in information about your environment. Then, nerves carry that data to and from your brain.

There are different types of neurons. Each type of neuron has a different job:

  • Motor neurons take signals from your brain and spinal cord to your muscles. They help you move. They also assist with breathing, swallowing and speaking.
  • Sensory neurons take information from your senses (what you see, touch, taste, etc.) to your brain.
  • Interneurons communicate between motor and sensory neurons. These neurons regulate your movement in response to sensory information (like moving away from a hot surface) and play a role in how you learn, think and remember.


What are the parts of the nervous system?

The nervous system has two main parts:

  • Central nervous system (CNS): Your brain and spinal cord make up your CNS. Your brain reads signals from your nerves to regulate how you think, move and feel.
  • Peripheral nervous system (PNS): Your PNS is made up of a network of nerves. The nerves branch out from your spinal cord. This system relays information from your brain and spinal cord to your organs, arms, legs, fingers and toes.

There are two parts to your peripheral nervous system:


What does the nervous system look like?

Nerve cells (neurons) are the basis of your nervous system. There are 100 billion neurons in your brain. These cells connect throughout your entire body.

Imagine your nervous system as a tree. Your central nervous system is the trunk of the tree that contains your brain and spinal cord. The tree branches are your peripheral nervous system (nerves). The branches extend from the truck (brain and spinal cord) to reach all parts of your body.

Conditions and Disorders

What are common conditions or disorders that affect the nervous system?

There are many conditions that affect your nervous system. Some of the most common include:

What are common signs or symptoms of nervous system conditions?

Signs and symptoms of nervous system conditions vary by type but may include:

  • Movement and coordination changes.
  • Memory loss.
  • Pain, numbness or a pins and needles feeling.
  • Behavioral and mood changes.
  • Difficulty with thinking and reasoning.
  • Seizures.

Some conditions, like a stroke, are medical emergencies that need treatment quickly. If you notice the following symptoms, contact 911 or your local emergency services number:

What tests check the health of your nervous system?

A healthcare provider may use one of the following tests to check the health of your nervous system:


How are conditions that affect the nervous system treated?

A healthcare provider will review your symptoms to diagnose and treat any conditions that affect your nervous system. Treatment varies for each condition. So, your healthcare provider will take into consideration several factors, like your age and general health, to create your treatment plan. This plan may include:

  • Taking medications.
  • Having surgery.
  • Participating in counseling for mental and emotional support.
  • Receiving supportive care (to keep you comfortable).


How do I keep my nervous system healthy?

You can keep your nervous system healthy by:

  • Seeing a healthcare provider regularly.
  • Maintaining good health (like eating balanced foods).
  • Avoiding harmful substances (like not smoking tobacco).
  • Wearing protective gear or equipment (a helmet) when playing sports or participating in certain activities.
  • Managing any underlying health conditions.

When should I call a healthcare provider?

Contact a healthcare provider right away if you notice sudden changes to your health like:

  • Muscle weakness.
  • Vision problems or severe headaches.
  • Slurred speech.
  • Numbness, tingling or loss of sensation in your arms or legs.
  • Tremors or tics (random muscle movements).
  • Changes in behavior or memory.
  • Problems with coordination or moving your muscles.

If you or a loved one shows signs of a stroke or seizure, contact 911 or your local emergency services number.

A note from Cleveland Clinic

Your nervous system is the command center for your entire body. It helps you think, learn, move and remember. This vast network of nerves connects to all of your organs, muscles and glands. It needs care to keep working. Sometimes, unexpected events can affect your nervous system, like an infection, injury or underlying condition. A healthcare provider can help you stay healthy so your nervous system has all it needs to function as expected.

Medically Reviewed

Last reviewed on 11/16/2023.

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