International Licensing Examination (ILE) Practice Test

What is the final transformation of energy in the inner ear before it reaches the brain?

1. From hydraulic to acoustic

2. From mechanical to hydraulic

3. From hydraulic to electrical

4. From mechanical to electrical

The correct answer is: From mechanical to electrical

The final transformation of energy in the inner ear before it reaches the brain involves converting mechanical energy into electrical energy. In the process of hearing, sound waves enter the ear canal and cause the tympanic membrane (eardrum) to vibrate, which converts sound waves into mechanical vibrations. These vibrations are transmitted through the three tiny bones in the middle ear—the malleus, incus, and stapes—before reaching the cochlea in the inner ear. Within the cochlea, these mechanical vibrations create waves in the fluid that moves hair cells against the tectorial membrane. When the hairs of these sensory hair cells bend due to the fluid movement, this mechanical action generates electrical impulses. These impulses are what are ultimately sent to the brain via the auditory nerve, translating the physical acoustic signals into perceptual sound. Understanding this process highlights the crucial role of the inner ear in transforming sound energy into a format that the brain can interpret, which is essential for the perception of sound.