By Denise DeWitt / EmpowHer Writer
When you think of your sense of balance, you may first think of what your eyes tell you about the position of your body: does the ground appear to be level or tilted? You may also consider what your bones and joints tell you: are your feet level or are you braced to one side? You may not realize that a significant source of balance information is located inside your inner ear.
As children, we test our sense of balance by walking on every narrow ledge we can find, progressing from painted lines on the parking lot to raised curbs to balance beams for those who are very skilled. One of the important sources of balance information for the brain is an organ in the inner ear called the labyrinth. The labyrinth is a cluster of connected passages and hollow tubes filled with fluid and lined with tiny hair-like sensors. When the fluid moves, these sensors create nerve impulses that are sent to the brain.
Parts of the Inner Ear
There are three parts of the labyrinth in the inner ear that are responsible for different types of sensory perception:
•Acceleration – the sensors in the center section of the labyrinth, which is called the vestibule, help your brain recognize when you accelerate movement in any direction. The brain can determine whether you are moving quickly or slowly, and whether you are speeding up or slowing down based on the movement of the fluid in this part of the ear.
•Hearing – the cochlea is a snail-shaped structure to one side of the vestibule. Sounds traveling into the ear cause tiny bones inside the middle ear to vibrate. These vibrations are transferred into the cochlea where they are translated into impulses that are sent to the brain.
•Balance – there are three loops or hollow tubes called semicircular canals that branch off from the vestibule on the other side from the cochlea. The hair-like sensors in these canals recognize when your head or body is rotated in any direction based on the movement of the fluid in the canal.
How Balance Works
The balance system in the ear works with the skeletal system (the muscles and joints) as well as with the visual system to send information to the brain about your body’s orientation and balance. The brain receives and compares information from all of these sources. For example, when we move quickly, the ear recognizes the movement and the brain coordinates with the eyes to make sure things stay in focus. This is why the eyes may seem to lag behind when a spinning motion is suddenly stopped. The ears recognize that the body is no longer spinning, triggering the brain to tell the eyes to stop compensating for the motion.
When the signals from these systems do not agree, we can become dizzy or motion sick, as may happen when reading in a moving car. When something goes wrong with these balance systems, a person may experience an on-going balance disorder including dizziness, blurred vision, lightheadedness, or a feeling of falling.
Sources:
National Institute on Deafness and Other Communication Disorders
Mayo Clinic
