Which structure detects angular acceleration?

Which structure detects angular acceleration?

• A. Linear acceleration
• B. Angular acceleration
• C. Gravity
• D. Endolymph composition

Answer: (B)

Angular acceleration is detected by the semicircular canals, which house the hair cells in the crista ampullaris of each ampulla. When the head starts to rotate, the endolymph fluid inside the canals lags behind due to inertia. That lag pushes on the cupula, bending the stereocilia of the hair cells. This deflection changes the cells’ firing rate, signaling a change in rotational velocity to the brain. Once rotation continues at a steady speed, the endolymph moves at the same rate as the canal and the deflection stops, so the signal tapers off. In contrast, linear acceleration and gravity are sensed by the otolith organs (utricle and saccule), and endolymph composition is not a sensory detector.

Angular acceleration is detected by the semicircular canals, which house the hair cells in the crista ampullaris of each ampulla. When the head starts to rotate, the endolymph fluid inside the canals lags behind due to inertia. That lag pushes on the cupula, bending the stereocilia of the hair cells. This deflection changes the cells’ firing rate, signaling a change in rotational velocity to the brain. Once rotation continues at a steady speed, the endolymph moves at the same rate as the canal and the deflection stops, so the signal tapers off. In contrast, linear acceleration and gravity are sensed by the otolith organs (utricle and saccule), and endolymph composition is not a sensory detector.