nociception (also nocioception or nociperception) is the encoding and processing of harmful stimuli in the nervous system, and, therefore, the ability of a body to sense potential harm. it is the afferent activity in the peripheral and central nervous systems produced by stimulation of specialized free nerve endings called "nociceptors" or "pain receptors" that only respond to tissue damage caused by intense chemical (e.g., chilli powder in the eyes), mechanical (e.g., pinching, crushing) or thermal (heat and cold) stimulation. once stimulated, a nociceptor sends a signal along a chain of nerve fibers via the spinal cord to the brain. nociception triggers a variety of autonomic responses and may also result in a subjective experience of pain in sentient beings. nociceptive neurons generate trains of action potentials in response to intense stimuli, and the frequency of firing determines the intensity of the pain. the three types of pain receptors are cutaneous (skin), somatic (joints and bones), and visceral (body organs). it was previously believed that pain was simply the overloading of sensory receptors, but research in the first half of the 20th century indicated that pain is a distinct phenomenon that intertwines with all of the other senses, including touch. pain was once considered a non-material experience, but recent studies show that pain is registered in specific parts of the brain. the main function of pain is to attract our attention to dangers and motivate us to avoid them. ==detection of noxious stimuli== potentially damaging mechanical, thermal
Nociception Pain Sensory_systems