What are the ossicles?

What are the ossicles?

• A. Three bones of the middle ear: malleus, incus, and stapes
• B. The three layers of the tympanic membrane
• C. The inner ear's cochlear hair cells
• D. The bony labyrinth

Answer: (A)

Ossicles are the three tiny bones in the middle ear that transmit and amplify sound vibrations from the eardrum to the inner ear. They form a lever-like chain—the malleus (hammer), incus (anvil), and stapes (stirrup)—that raises the pressure of the vibrations so they can move the fluid in the cochlea. This helps overcome the impedance difference between air and the inner-ear fluids, making hearing more efficient. The other options describe parts that aren’t the ossicles: the tympanic membrane has multiple layers and is the eardrum, not the bones; the cochlear hair cells are sensory receptors in the inner ear; and the bony labyrinth is the rigid outer portion of the inner ear, not the middle-ear bones.

Ossicles are the three tiny bones in the middle ear that transmit and amplify sound vibrations from the eardrum to the inner ear. They form a lever-like chain—the malleus (hammer), incus (anvil), and stapes (stirrup)—that raises the pressure of the vibrations so they can move the fluid in the cochlea. This helps overcome the impedance difference between air and the inner-ear fluids, making hearing more efficient. The other options describe parts that aren’t the ossicles: the tympanic membrane has multiple layers and is the eardrum, not the bones; the cochlear hair cells are sensory receptors in the inner ear; and the bony labyrinth is the rigid outer portion of the inner ear, not the middle-ear bones.