Definition: Nociceptors are a specific subset of peripheral sensory organs which respond to noxious stimuli. A mechanoreceptors and C-polymodal nociceptors are the two main classes of cutaneous nociceptors. The sensory quality of pain evoked by activation of A-fibers is generally described as 'pricking', whereas that evoked by activation of C-fibers is generally described as 'burning'.
A structure that recognises signals from inside or outside the body, including temperature, pressure and chemicals. When activated, it sends signals to nerve cells, which carry the messages to the central nervous system (the spinal cord and brain).
A free nerve ending which detects noxious stimuli - chemical, mechanical and thermal. When tissue is damaged a variety of chemicals are released or synthesised, including histamine, potassium ions, bradykinin and prostaglandins. The body's own chemicals thereby stimulate these receptors in response to actual or potential damage, and this can be perceived as pain.
A nociceptor is a sensory receptor that sends signals that cause the perception of pain in response to potentially damaging stimulus. Nociceptors are the nerve endings responsible for nociception, one of the two types of persistent pain (the other, neuropathic pain, occurs when nerves in the central or peripheral nervous system are damaged). When they are activated, nociceptors can trigger a reflex.