Which is responsible for maintaining equilibrium?

• A. Semicircular canals
• B. Cochlea
• C. Auditory canal
• D. Eardrum

Answer: (A)

Semicircular canals detect rotational head movements and drive balance. In the inner ear’s vestibular system, each canal ends in a swelling called the ampulla with hair cells embedded in a gelatinous cupula. When the head rotates, the endolymph fluid lags behind, bending the cupula and the hair cells, which generates nerve signals about angular acceleration to the brain. This input helps maintain equilibrium and coordinate gaze through reflexes like the vestibulo-ocular reflex. The cochlea handles hearing, converting sound vibrations into neural signals, while the auditory canal and eardrum are part of the passage that collects and transmits sound. They don’t regulate balance.