What do semicircular canals detect?

What do semicircular canals detect?

• A. Changes in speed and direction, including yaw, pitch, and roll
• B. Gravity only
• C. Auditory signals
• D. Linear acceleration

Answer: (A)

Rotational movement of the head is what the semicircular canals sense. They respond to changes in rotational speed and direction around three perpendicular axes—yaw, pitch, and roll. Inside each canal, hair cells sit in a structure called the ampulla and are stimulated by the movement of endolymph fluid when the head rotates. Because the endolymph lags behind the moving head, it drags the cupula and bends the hair cells, sending nerve signals that reflect angular velocity rather than constant rotation. A key point is that these canals signal changes in rotation, not gravity or linear motion. Gravity and linear acceleration are detected by the otolith organs (saccule and utricle), while hearing involves the cochlea. So the best answer is that the semicircular canals detect changes in speed and direction of rotation, including yaw, pitch, and roll.

Rotational movement of the head is what the semicircular canals sense. They respond to changes in rotational speed and direction around three perpendicular axes—yaw, pitch, and roll. Inside each canal, hair cells sit in a structure called the ampulla and are stimulated by the movement of endolymph fluid when the head rotates. Because the endolymph lags behind the moving head, it drags the cupula and bends the hair cells, sending nerve signals that reflect angular velocity rather than constant rotation.

A key point is that these canals signal changes in rotation, not gravity or linear motion. Gravity and linear acceleration are detected by the otolith organs (saccule and utricle), while hearing involves the cochlea. So the best answer is that the semicircular canals detect changes in speed and direction of rotation, including yaw, pitch, and roll.