Loss of balance and head tilting in cats can indicate an inner ear infection. Which structure is associated with this observation?

The vestibule is the correct answer because it is a part of the inner ear that plays a crucial role in maintaining balance and equilibrium. It contains structures that contribute to the body's sense of spatial orientation, including the utricle and saccule, which are sensitive to changes in head position and linear acceleration. When there is an inner ear infection, these structures can become inflamed or compromised, leading to symptoms such as loss of balance and head tilting observed in cats.

The cochlea, while also part of the inner ear, is primarily responsible for hearing rather than balance. It converts sound vibrations into neural signals but does not contribute to the body’s equilibrium or spatial awareness. The auditory canal is involved in channels for sound to travel to the tympanic membrane (eardrum) but does not directly relate to balance. The tympanic membrane serves as a barrier between the outer ear and the middle ear, playing a role in the hearing process but not in vestibular function. Thus, the vestibule is specifically linked to balance-related issues, making it the correct response to the question about symptoms related to inner ear infections in cats.