Ear anatomy 101
The ear consists of three sections: outer, middle and inner ear. Each section performs a distinct function in the transmission of sounds to the brain. When any part of this system breaks down, hearing loss can result.
The outer ear consists of the pinna and external ear canal. The function of the outer ear is to collect sounds (at this point, vibrations) from the environment and to transmit the signal to the middle ear. The pinna assists in localizing the sound source and provides natural directional benefit. The external ear canal—typically “S” shaped and one inch long in adults—serves to funnel vibrations to the middle ear.
The middle ear begins at the tympanic membrane (ear drum) and ends at the inner ear. An air-filled space (called the middle ear cavity) is on the inner side of the ear drum. In that cavity are the ossicles (the three smallest bones in the human body): the malleus (hammer), incus (anvil) and stapes (stirrup). Sound vibrates the ear drum, which causes a chain reaction among the auditory bones, ending with the stapes vibrating the oval window of the cochlea in the inner ear.
In the inner ear, the cochlea is responsible for converting those vibrations into electrical signals that travel to the brain. The pressure on the oval window creates a complex wave-like motion that activates thousands of microscopic hair cells in the organ of corti, which are tuned to certain sound frequencies. When these hair cells are activated, they send electrical impulses through the auditory nerve to the hearing center of the brain, which translates them to sounds the brains can recognize.
The inner ear also includes the semi-circular canals, which are responsible for balance.
Learn more during Better Hearing Month
With May being Better Hearing Month, now is a great time to learn more about hearing and hearing loss. Arrange a free consultation by filling out our Contact Us page or calling us today.
Patricia Larson Shields, AuD FAAA MACCCSP/L is a doctor of audiology with her degree from The School of Audiology of the Pennsylvania College of Optometry in February, 2003. She has been in business in Mitchell, SD since September, 1991.