Functions of the Inner Ear

The inner ear is a small, fluid-filled space that has two main functions: hearing and balance. The inner ear contains many structures and has a complex anatomy that provides these important functions.

• The inner ear is responsible for hearing and balance.

Basic Inner Ear Anatomy

• The inner ear, also called the labyrinth, has a bony labyrinth and a membranous labyrinth. The bony labyrinth is a series of channels in the bone. The bony labyrinth contains a fluid called perilymph and the membranous labyrinth. The membranous labyrinth is a collection of interconnecting sacs and ducts that contains a fluid called endolymph.

  The three regions of the labyrinth that provide the functions of the inner ear are the cochlea, vestibule and semicircular canals.

Hearing

• The cochlea is responsible for hearing. The cochlea contains nerves that change energy vibrations in the inner ear fluid into nerve impulses that are sent to the brain to become sound. Damage to the cochlea can come from being hit in the head; nose, dental or head surgery; repeated exposure to loud noise (machinery, gunfire, music, etc.); or inserting sharp objects into the ear to remove wax.

Balance

• The vestibule and semicircular canals maintain your body's balance or equilibrium. The vestibule has two segments called the utricle and saccule, which determine your orientation to gravity by detecting linear accelerations. In contrast, the semicircular canals give information about turning, such as detecting rotational movements of the head.

  In other words, these structures detect the movement of your body and send signals to your brain that tell it if you are moving forward, back, up, or down or if you are turning and how fast you are moving. Your brain uses this information to keep you in a balanced position.

Inner Ear Dysfunction

• Problems with the cochlea can lead to hearing loss or deafness. Problems with the vestibule or semicircular canals can lead to balance problems, dizziness or vertigo (the false sense of motion or spinning). According to NIH Senior Health, balance disorders are one reason older people fall.

Balance Disorders

• According to the Massachusetts Eye and Ear Infirmary, balance problems can be caused by a long list of inner ear disorders, including Meniere's disease, benign paroxysmal positional vertigo (BPPV), degenerative disorders of the balance organs, drug toxicity, inner ear trauma from head injury or sudden pressure changes, and viral inflammation. If you experience balance problems, dizziness or vertigo, it's important to be properly diagnosed and treated.