Anatomy of the Inner Ear
Hearing is made up of two components – mechanical and nerve (or electrical). The mechanical part picks up sound from the outer ear canal which then vibrates the ear drum and three tiny hearing bones in the middle ear. The inner ear hearing apparatus looks a bit like a snail. This fluid-filled coil, or cochlea, acts like a telephone by converting the vibration (sound wave) into electric signals (electrical impulses) that are relayed to the brain via the vestibulo-cochlear (vestibular) nerve.
Read more: The Basics of Hearing and Hearing Loss
The other half of the inner ear is the balance, or vestibular system. There are two different working parts of the vestibular system: the semi-circular canals and the otoliths. The three canals are each oriented in different directions. Depending on which way you turn, fluid moves within the canals and is detected by receptors that send information to the brain by way of the vestibular nerve. This information tells your eyes which way you turned your head so that you can keep your eyes focused on an object in front of you, such as the words on this page. The otoliths (saccule and utricle) have a different function; they inform your muscles if you tilt, speed up or slow down, such as in elevators or airplanes. This information subtly adjusts your muscles so that you can maintain your standing or walking balance.
The inner ear is bathed in fluid on the outside (perilymph) and fluid on the inside (endolymph). The endolymph undergoes a natural recycling every day and is created and absorbed by the endolymphatic sac.
Closely associated to the ear is the facial nerve. It is responsible for sensation, face-muscle movement, and it provides some of the taste to the tip of the tongue.