Final answer:
Nociceptors are nonadapting receptors that detect painful stimuli, initiating nociception by responding continuously to harmful or damaging inputs and contributing to the perception of pain in the brain.
Step-by-step explanation:
Nociceptors, or receptors that perceive painful stimuli, are referred to as nonadapting because they are designed to continuously respond to potentially harmful or damaging stimuli. These receptors are involved in the process of nociception, which is the sensation of pain triggered by mechanical, thermal, or chemical stimuli beyond a threshold that can cause tissue damage. When activated, nociceptors send signals through various nociceptive pathways to the brain where the sensation of pain is perceived. For example, capsaicin from spicy foods binds to transmembrane ion channels in nociceptors, activating them and causing a sensation of heat or pain, which is why capsaicin can also be used in products like Icy Hot™ as a topical analgesic.