You accidentally touch a hot stove. In a millisecond, you jerk your hand away. What just happened? You have pain receptors throughout your body, both outside and within. These receptors send electrical messages through your spinal cord to the brain. You only become aware of pain after your brain receives and interprets these electrical messages. In some cases, such as when you touch a hot stove, the body can spring into defensive action even before the brain knows what is happening. That's because pain messages that reach the spinal cord can cause an automatic reflex response, making muscles near the source of the pain contract to get away from the pain.
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