The ear is a very delicate system divided into three sections -- outer ear, middle ear, and inner ear. Each section plays an important role in how precisely we hear sounds. The outer ear and middle ear are separated by a thin, cone-shaped skin or membrane, less than half an inch wide, known as the tympanic membrane, or more commonly called the eardrum. The eardrum is the only sensory portion of the ear and, though rigid, it is extremely sensitive to even the most minute air pressure fluctuations. Both sides of the eardrum are exposed to air from the atmosphere. Air from the environment enters the outer ear hitting the eardrum on one side, while air from the mouth travels up the eustachian tube hitting it from the other side. This forces equal amounts of air pressure to build up on both sides of the eardrum, allowing it to be gently moved back and forth.

Main functions of the eardrum
o Changes sound waves from the atmosphere into sound vibrations that can be picked up by the bones of the middle ear.
The eardrum is attached to a very tiny muscle called the tensor tympani muscle. It is this little muscle that keeps the eardrum taut so that it will vibrate back and forth no matter how slight the sound waves, or which part of it is hit by the sound waves. As the sound waves entering the ear canal hits the eardrum it responds like the diaphragm of a microphone with contractions and rarefactions of each sound wave, eliciting a different response to the various types of sounds. High-pitched sounds cause it to move more quickly, while sounds that are louder force the eardrum to move much further.
o Protects the inner ear from prolonged exposure to loud, low-pitched noises.
The eardrum is also a protector of our hearing. To protect the inner ear from prolonged exposure to loud, low-pitched noises, the tensor tympani muscle, along with the stapedius reflex muscle, contracts immediately as soon as the brain perceives the presence of the damaging noise. This contraction results in the eardrum being pulled in one direction and the bones of the middle ear being pulled in the opposite direction, forcing the eardrum to become even more rigid and thereby dampening the effects of the harmful noise to our hearing.
oAssists understanding of conversational speech when background noise is present.
Another amazing thing about the eardrum is that the reflex also masks loud, low-pitched background noises, allowing us to focus our hearing and thereby improving our ability to hear softer, high-pitched conversational speech sounds when loud, low-pitched background noise is present.
o Helps monitor the loudness level of our voice.
To ensure that when we speak, the sound of our own voice does not overwhelm or drown out the other sounds around us, the reflex is once again activated. This allows us to hear our voice at a comfortable level as we speak, while simultaneously enjoying the other sounds around us.
The eardrum is a part of our amazing hearing system and is essential in our ability to hear precisely.

o For further information on any hearing-related disorder, please contact Dr. Deborah Nubirth, doctor of audiology, in New Providence at Comprehensive Family Medical Clinic, Poinciana Drive at 356-2276 or 677-6627 or 351-7902 in Grand Bahama; or email dnubirth@yahoo.com.

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