I’ve had a colonoscopy (without pain relief) where they took biopsies. The doctors said the biopsies wouldn’t hurt because the colon couldn’t feel pain, and they were indeed painless. The amount of air they pumped in was horrifically painful however.
Trapped gas sounds trivial, but can also be extremely painful. Ulcerative colitis also hurts. So does diarrhoea.
So how do these pain mechanisms work? What causes the pain, if the interior of the colon is unfeeling?
In: Biology
Víscera like the intestine, kidneys, liver, lungs etc, have non precise pain receptors on the outer layer. That’s why this kind of pain is diffuse and not very precise. This means that there is no pain in the inside. That’s why a tumor doesn’t hurt until it affects the outside layer, either by stretching or damaging it. In the case of the intestines, they get stretched causing pain.
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