Pain

This is a sensation that occurs when tissues are damaged and triggers protective reactions. Pain receptors, i.e. nociceptors, are nerve endings sensitive to pain. They are found everywhere except in the brain tissue and liver parenchyma. Nociceptors are not specific to one stimulus, they can be activated by mechanical, chemical, and temperature stimuli. Nociceptors are stimulated by pain-inducing chemicals released when tissues are damaged. These include bradykinin, serotonin, histamine, prostaglandins, and others.

Body pain is classified as follows:

– superficial, occurring in the skin;

– deep, arising from muscles, joints, bones.

Superficial pain is sharp, its location is clearly felt, it spreads to the central nervous system through third group fibers. Deep body pain and visceral pain are dull in nature, with an imprecise location, spreading through slow fourth group fibers.

Long-term pain causes changes in physiological parameters: blood pressure, heart rate, hormone concentration, and other parameters fluctuate.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė