Which statement about the crista ampullaris is true?

Which statement about the crista ampullaris is true?

• A. It detects gravity.
• B. It detects linear acceleration.
• C. It processes auditory signals.
• D. It encodes rotational movement of the head.

Answer: (D)

The crista ampullaris is the sensor for angular (rotational) movement of the head. It sits in the ampulla of each semicircular canal and contains hair cells with stereocilia and a kinocilium embedded in a gelatinous cupula. When the head rotates, the inertia of the endolymph causes it to lag behind, bending the cupula and deflecting the hair bundles. This deflection changes the hair cells’ neurotransmitter release and sends signals via the vestibular nerve to the brain, encoding rotational acceleration. In contrast, gravity and linear acceleration are detected by the otolith organs (utricle and saccule), and auditory signals are processed by the cochlea, not the crista ampullaris.

The crista ampullaris is the sensor for angular (rotational) movement of the head. It sits in the ampulla of each semicircular canal and contains hair cells with stereocilia and a kinocilium embedded in a gelatinous cupula. When the head rotates, the inertia of the endolymph causes it to lag behind, bending the cupula and deflecting the hair bundles. This deflection changes the hair cells’ neurotransmitter release and sends signals via the vestibular nerve to the brain, encoding rotational acceleration. In contrast, gravity and linear acceleration are detected by the otolith organs (utricle and saccule), and auditory signals are processed by the cochlea, not the crista ampullaris.