What are mechanical nociceptors?

• A. Respond most to sharp pressure
• B. Respond to heat
• C. Respond to chemical irritants
• D. Respond to vibration

Answer: (A)

Mechanical nociceptors are nerve fibers that detect damaging mechanical energy. They respond most to sharp pressure, such as a pinching or cutting force on tissue, because that kind of mechanical input risks injury and produces a quick, well-localized pain signal. This high threshold for mechanical stimuli distinguishes them from other nociceptors: thermal nociceptors respond to heat, chemical nociceptors respond to irritants or inflammatory chemicals, and vibration is typically handled by non-nociceptive mechanoreceptors. While some nociceptors can be polymodal and respond to multiple harmful stimuli, the hallmark for mechanical nociceptors is their strongest responsiveness to sharp pressure.