Meniere's disease primarily affects which structure of the ear?

Meniere's disease is a disorder that predominantly impacts the inner ear, specifically affecting the cochlea and the vestibular system. This condition is characterized by episodes of vertigo, tinnitus, a feeling of fullness in the ear, and fluctuating hearing loss. The primary issue in Meniere's disease is related to an abnormal accumulation of fluid in the inner ear's labyrinth, which includes the cochlea. The cochlea is crucial for hearing, as it converts sound vibrations into nerve signals that are sent to the brain. The cochlea's involvement is central to the auditory symptoms experienced by individuals with Meniere's disease. As a result, this makes it clear that the cochlea is the correct answer in identifying the structure of the ear primarily affected by Meniere's disease.