Physiologically, the middle ear, containing the three ossicles, serves primarily to:
1. Maintain balance.
A. Maintain balance.
B. Translate sound waves into nerve impulses.
C. Amplify the energy of sound waves entering the ear.
D. Communicate with the throat via the Eustachian tube.
Correct Answer: C. Amplify the energy of sound waves entering the ear.
The middle ear contains the three ossicles—malleus, incus, and stapes—which, along with the tympanic membrane and oval window, form an amplifying system. These bony structures are suspended by ligaments which make them suitable for transmission of vibrations into the inner ear. The vibrations that come into this part of the middle ear then get transmitted by the action of the stapes, into the inner ear.
Option A: The inner ear is a space composed of the bony labyrinth and the membranous labyrinth, one inside the other. The bony labyrinth has a cavity filled with semicircular canals that are in charge of sensing equilibrium; this cavity is called the vestibule and is the place where the vestibular part of the VIII cranial nerve forms.
Option B: The first transformation consists of the conversion of air vibrations into tympanic membrane vibrations. These vibrations then get transmitted into the middle ear and the ossicles. Then these vibrations transform into liquid vibrations in the inner ear and the cochlea, and these stimulate a region called the basilar membrane and the organ of Corti. Finally, these vibrations get transformed into nerve impulses, which travel to the nervous system.
Option D: The Eustachian tube plays a role in equalization, oxygenation, and drainage of the tympanic cavity in the middle ear. More specifically, the Eustachian tube permits equalization of pressure in the middle ear with respect to ambient pressure. In doing so, the Eustachian tube allows for regulation of the pressure across the tympanic membrane.
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