What are nociceptors?

What are nociceptors?

• A. Specialized sensory neurons that detect harmful (noxious) stimuli
• B. Cells in the CNS that interpret pain
• C. Nerve fibers that carry only temperature signals
• D. Receptors that dampen pain signals

Answer: (A)

Nociceptors are specialized sensory neurons in the periphery that detect potentially harmful, noxious stimuli. They are usually free nerve endings in tissues like skin, joints, and organs, and they respond to mechanical damage, extreme temperatures, or chemical irritants. When activated, they convert the stimulus into electrical signals that travel via small-diameter pain fibers (A-delta for fast, sharp pain and C fibers for slower, dull pain) to the spinal cord and brain, producing the sensation of pain. They are distinct from thermoreceptors or mechanoreceptors that sense non-painful stimuli, and they don’t dampen pain signals themselves—pain modulation occurs through other pathways. Inflammation can sensitize nociceptors, lowering their threshold and leading to increased pain perception.

Nociceptors are specialized sensory neurons in the periphery that detect potentially harmful, noxious stimuli. They are usually free nerve endings in tissues like skin, joints, and organs, and they respond to mechanical damage, extreme temperatures, or chemical irritants. When activated, they convert the stimulus into electrical signals that travel via small-diameter pain fibers (A-delta for fast, sharp pain and C fibers for slower, dull pain) to the spinal cord and brain, producing the sensation of pain. They are distinct from thermoreceptors or mechanoreceptors that sense non-painful stimuli, and they don’t dampen pain signals themselves—pain modulation occurs through other pathways. Inflammation can sensitize nociceptors, lowering their threshold and leading to increased pain perception.