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The nervous system is your body's Internet. This is where feelings, memories and information is continuously circulated throughout the body to make us act in different ways.
The nervous system is made up of three parts:
- The brain
- The spinal cord
- The nerves
The brain
The brain is the central computer; you might even say the hard drive. It receives information from the nerves. It either saves this information or instructs the body to do something.
The spinal cord
The spinal cord is a cable about 1 cm in diameter that runs from the brain through the canal that the holes in the middle of the vertebrae form. From the spinal cord, nerves spread out to all parts of your body. However, the nerves that go to the eyes, the ears and other parts of the head go directly from the brain, not via the spinal cord.
The nerves
There are two kinds of nerves. One kind carries information to the spinal cord and the brain. The other kind carries orders from the brain and the spinal cord.
A message from your toes to your brain could sound like this: "The water is cold." The message from your toes is sent by a nerve to the spinal cord from which it is passed on up to the brain. The brain gives an order: "Pull the toes out of the water!" This order is passed through the spinal cord and along a nerve to the leg muscle that can pull your toes out of the water.
Sometimes you need to act fast. If you touch a very hot cooking pot, the message only goes to the spinal cord which then immediately gives your arm muscle an instruction to pull your hand away from the cooking pot. This is called a reflex action. If this message had been forced to go all the way to the brain and the order, to release the pot, had been forced to make the entire journey back, you might have burned yourself.
Other reflex actions are blinking and sneezing.
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