What are proprioceptors?

• A. Receptors that detect body position and movement, such as hair plates at leg joints
• B. Nociceptors for pain perception
• C. Photoreceptors in the compound eye
• D. Chemoreceptors for pheromones

Answer: (A)

Proprioception is the sense of body position and movement, and it relies on proprioceptors—specialized mechanoreceptors that monitor limb position, muscle stretch, and joint angles. In insects and other arthropods, hair plates at leg joints are classic proprioceptors. When a joint moves, tiny hairs deflect, the mechanosensitive channels open, and signals are sent to the nervous system to inform it about the current position and movement of the limb. This feedback helps coordinate gait and posture automatically.

The other receptor types describe different senses: nociceptors detect tissue damage and pain, photoreceptors detect light for vision, and chemoreceptors detect chemical signals such as pheromones. These are not about the position or movement of the body, which is why they don’t fit the role of proprioceptors.