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Pain perception
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Pain perception starts with nociception, the information that nerves send to the central nervous system so it can detect and avoid whatever might harm the body. It is not pain yet: it is the warning that something harmful is there.
That detection is carried out by nociceptors, neurons specialized in detecting harmful stimuli. When heat, cold, mechanical force, or a chemical substance reaches a nociceptor, the stimulus opens cation channels, pores that let positively charged particles through. As those charges enter, the cell depolarizes, meaning its electrical charge shifts and the signal starts.
From there the signal can take two routes. One is a spinal reflex, which is handled in the spinal cord and pulls the affected part away immediately. The other route travels up to the brain areas that integrate that information with higher-order sensations, and that is where pain itself appears. There are two routes: the reflex that jerks the hand back before you think, and the warning that reaches the brain afterward.
In brief
Nociception is the nerve signaling that lets the central nervous system detect and avoid harmful stimuli.
Heat, cold, mechanical force, or a chemical stimulus opens cation channels in the nociceptor and depolarizes it.
That signal either branches into a spinal reflex that pulls the affected part away, or travels up to the brain areas that integrate it as pain.
There are two routes: the reflex that jerks the hand back before you think, and the warning that reaches the brain afterward.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Nociception, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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