Which component detects angular acceleration in the vestibular system?

Which component detects angular acceleration in the vestibular system?

• A. Semicircular Canals
• B. Otolith Organs
• C. Cochlea
• D. Eustachian Tube

Answer: (A)

Angular acceleration is detected by the semicircular canals. These three loops are oriented in perpendicular planes and each contains hair cells in a structure called the ampulla with a gelatinous cupula. When the head begins to rotate, the endolymph inside the canals lags behind due to inertia, pushing against the cupula and deflecting the hair cells. This changes the firing rate of vestibular nerve fibers, signaling a change in rotational speed. As rotation becomes steady, the endolymph catches up and no longer deflects the cupula, so the signal returns toward baseline. The otolith organs detect linear acceleration and head orientation relative to gravity, not angular acceleration; the cochlea handles hearing; and the Eustachian tube mainly equalizes middle-ear pressure.

Angular acceleration is detected by the semicircular canals. These three loops are oriented in perpendicular planes and each contains hair cells in a structure called the ampulla with a gelatinous cupula. When the head begins to rotate, the endolymph inside the canals lags behind due to inertia, pushing against the cupula and deflecting the hair cells. This changes the firing rate of vestibular nerve fibers, signaling a change in rotational speed. As rotation becomes steady, the endolymph catches up and no longer deflects the cupula, so the signal returns toward baseline. The otolith organs detect linear acceleration and head orientation relative to gravity, not angular acceleration; the cochlea handles hearing; and the Eustachian tube mainly equalizes middle-ear pressure.