The organ of Corti contains inner and outer hair cells. Which structure carries afferent signals from the inner hair cells to the central auditory system?

• A Radial fibers of the cochlear nerve (spiral ganglion type I neurons innervating predominantly inner hair cells) ✓
• B Outer spiral fibers innervating outer hair cells exclusively
• C Vestibular nerve fibers
• D Olivocochlear bundle (efferent fibers from the superior olivary complex)

Explanation

Approximately 90–95% of afferent cochlear nerve fibers are type I spiral ganglion neurons that form radial fibers and innervate predominantly inner hair cells (each inner hair cell receives 10–20 type I fibers). Despite being fewer in number, inner hair cells carry the principal afferent auditory signal. The remaining 5–10% are type II spiral ganglion neurons (outer spiral fibers) innervating outer hair cells but with sparse synaptic contacts. The olivocochlear bundle is efferent (motor) and modulates outer hair cell function. The vestibular nerve carries balance signals.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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