A noxious stimulus is a stimulus strong enough to threaten the body’s integrity (i.e. cause damage to tissue). Noxious stimulation induces peripheral afferents responsible for transducing pain (including A-delta and C- nerve fibers, as well as free nerve endings), throughout the nervous system of an organism. The ability to perceive noxious stimuli is a prerequisite for

nociception Nociception (also nocioception, from Latin ''nocere'' 'to harm or hurt') is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, ...

, which itself is a prerequisite for

nociceptive pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

. A noxious stimulus has been seen to drives nocifensive behavioral responses, which are responses to noxious or painful stimuli. These include reflexive, escape behaviors, to avoid harm to an organism's body. Because of rare genetic conditions that inhibit the ability to perceive physical pain, such a
congenital insensitivity to pain and anhydrosis (CIPA)
noxious stimulation does not invariably lead to tissue damage. Noxious stimuli can either be mechanical (e.g. pinching or other tissue deformation),

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...

(e.g. exposure to acid or irritant), or

thermal A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...

(e.g. high or low

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on ...

s). There are some types of tissue damage that are not detected by any sensory receptors, and thus cannot cause pain. Therefore, not all noxious stimuli are adequate stimuli of nociceptors. The adequate stimuli of nociceptors are termed ''nociceptive stimuli''.

References

{{Pain Pain Nociception Sensory systems