有關biology question

Nervous system is made up of two divisions, the central nervous system and the peripheral nervous system. The central nervous system is made up of the brain and spinal cord, while the peripheral nervous system is made up of everything else.
The nerves of the peripheral nervous system can be divided into two groups, the somatic and autonomatic. The somatic nerves control voluntary actions, and the autonomatic nerves control involuntary actions.
Sometimes your body moves with out you thinking about it. When this happens it is called a reflex. A reflex is an automatic response that occurs without conscious control. Usually your movements are are controlled by the brain. With reflexes your body feels that you are in danger and acts with out your brain. Sensory neurons travel to your spinal cord, and transfer the the impulse to interneurons. These interneurons take the impulse back to the point of origin and signal that body part to move. Without reflexes we could get seriously hurt.

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