Which structure in the ear is responsible for equilibrium?

The semicircular canals are crucial for maintaining equilibrium, which is the body's ability to maintain balance. These structures are part of the vestibular system located in the inner ear. Each semicircular canal is oriented in a different plane and is filled with fluid. When the head moves, the fluid inside the canals shifts, which stimulates sensory hair cells. This stimulation sends signals to the brain about the position and motion of the head, allowing the body to maintain balance and spatial orientation.

In contrast, the cochlea is primarily responsible for hearing, converting sound vibrations into nerve signals for the auditory pathway. The Eustachian tube helps to equalize pressure in the middle ear but does not play a role in balance. The auditory canal is part of the pathway that directs sound waves to the tympanic membrane (eardrum) and is also not involved in equilibrium.