Pain results from a series of exchanges among three major components of your nervous system:
Your peripheral nerves These nerves extend fromyour spinal cord to your skin,
muscles, bones, joints and internal organs. Some peripheral nerve fibers end with receptors that respond to touch, pressure, vibration, cold and warmth
Your spinal cordThe nerve fibers that transmit pain messages — such as the
throbbing pain from that stubbed toe — enter the spinal cord in an area called the dorsal
horn. There, they release chemicals(neurotransmitters) that activate other nerve cells in the spinal cord, which process the information and then transmit it up to the brain.
Your brain When news of your stubbed toe travels up the spinal cord, itarrives at
the thalamus — a sorting and switching station deep inside your brain.
Some of our current understanding of pain is based on the "gate-control theory," which
grew out of observations ofWorld War II veterans and their reactions to different types of injuries. The central concepts of gate-control theory are:
Pain messages don't travel directly from y our pain receptors to your
brain. When pain messages reach your spinal cord, they meet up with specialized nerve
cells that act as gatekeepers, which filter the pain messages on their way to your brain.
For severe pain that'slinked to bodily harm, such as when you touch a hot stove, the "gate" is wide open, and the messages take an express route to your brain. Weak pain messages,however, may be filtered or blocked out bythe gate.
Nerve fibers that transmit touch also affect gatekeeper cells. This explains why rubbing a sore area — such as the site of a stubbed toe — makes it feel better. The signals of touch from therubbing actually decrease the transmission of pain signals.
Messages can change within your peripheral nerves and spinal cord.
Nerve cells in your spinal cord may release chemicals that intensify...