How does a problem in the body (other than hurting yourself) get translated into pain (for example stomach pain)?
In: Biology
Muscle pain is the sensory nerve receptors responding to local inflammation or injury. This includes the lack of oxygen induced by exercise. Heart pain is most often a form of muscle pain in the heart, when it can’t get enough oxygen to work optimally.
Headaches can have many and varied causes, but most often it is a “relaxed” artery. We have muscles around all our circulatory system, and relaxed arteries or veins enlarge (decreasing blood pressure).
We actually don’t have any sensory nerves in the brain, so what we call a headache is usually a “relaxed” artery constricting a facial nerve. Sort of like carpal tunnel syndrome but with a blood vessel.
Stomach pain can be caused by many things – eating too much stretches it, which hurts. Not eating and drinking enough makes the stomach more acidic (because there’s no water or food to dilute the acid) which strains the membranes as well.
It can also be neurologically induced, such as that induced by alcohol, amphetamines, ecstacy, psychedelics or opioids. Dopamine, Norepinephrine, Serotonin and Epinephrine/Adrenaline can all induce stomach pain, nausea or even vomiting in excess amounts.
This is why for example infatuation, nervousness or anxiety is associated with stomach pain and nausea.
Intestinal pain can be associated with constipation, diarrhea or changes in how the intestinal muscles operate. Same as blood vessels, our intestines can relax (widening them and causing diarrhea) or constrict (constricting them and causing constipation). All the above neurotransmitters also impact the intestines in both directions.
Pain in various areas caused by pathogenic infection (influenza, COVID, stomach flu, food poisoning etc) is because the destruction of cells causes the release of pro-inflammatory “signal chemicals”. In extreme cases, this can also be the case with muscle pain if you exercise to the point that they start breaking apart.
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