Which vestibular component detects angular acceleration of the head?

• A. Semicircular canals
• B. Cochlea
• C. Otolith organs
• D. Utricle

Answer: (A)

Rotational (angular) movement of the head is detected by the semicircular canals. Each canal has a sensory region called the crista ampullaris with hair cells. When you rotate, the endolymph fluid inside the canal lags behind due to inertia, bending the cupula and deflecting the hair bundles. This bending changes the firing rate of the vestibular nerve, signaling the direction and speed of rotation. Because the canal response is strongest when rotation starts or stops, it encodes changes in angular velocity, i.e., angular acceleration. The other vestibular components don’t track rotation: the cochlea handles hearing, and the otolith organs (utricle and saccule) detect linear acceleration and head tilt relative to gravity, not angular movement.