AP Psychology Practice Test

What does the middle ear contain?

1. Three tiny bones that transmit vibrations to the cochlea.

2. The eardrum and cochlear nerve.

3. Fluid that converts sound waves to nerve impulses.

4. Semicircular canals for balance.

The correct answer is: Three tiny bones that transmit vibrations to the cochlea.

The middle ear contains three tiny bones known as the ossicles, which are the malleus (hammer), incus (anvil), and stapes (stirrup). These bones play a crucial role in the process of hearing; they transmit vibrations from the eardrum to the cochlea in the inner ear. When sound waves hit the eardrum, it vibrates, and these vibrations are amplified and transferred through the ossicles before reaching the cochlea, where they are converted into nerve impulses for the brain to interpret as sound. The other options describe components found in different parts of the ear. The eardrum is part of the outer ear, and the cochlear nerve is associated with the inner ear, not the middle ear specifically. Fluid is indeed present in the inner ear as part of the cochlea but does not exist in the middle ear, which is a space that connects the outer ear to the inner ear. Lastly, semivircular canals are structures related to balance and are also part of the inner ear, further differentiating them from the middle ear's primary role in hearing.