The ossicles:
a. directly connect the tympanic membrane with the tectorial membrane
b. provide mechanical advantage for the transmission of force to the oval window
c. are composed of the incus, malleus, stapes, and pinna
d. are tiny muscles providing mechanical force to dampen sound
The correct answer and explanation is :
Correct Answer: (b) provide mechanical advantage for the transmission of force to the oval window
Explanation:
The ossicles are the three tiny bones in the middle ear: the malleus (hammer), incus (anvil), and stapes (stirrup). Their primary function is to transmit and amplify sound vibrations from the tympanic membrane (eardrum) to the oval window of the cochlea in the inner ear.
Why is (b) correct?
The ossicles act as a mechanical lever system that enhances the efficiency of sound transmission. Since sound waves travel from air (outer ear) to the fluid-filled cochlea (inner ear), there is a natural loss of energy due to the difference in medium. The ossicles compensate for this by providing a mechanical advantage, amplifying the force applied to the oval window. The malleus receives vibrations from the tympanic membrane, transmits them to the incus, which then passes the vibrations to the stapes. The stapes, in turn, pushes against the oval window, creating fluid waves in the cochlea, essential for hearing.
Why are the other options incorrect?
- (a) Directly connect the tympanic membrane with the tectorial membrane → Incorrect because the tectorial membrane is part of the cochlea in the inner ear, not the middle ear where the ossicles are located.
- (c) Are composed of the incus, malleus, stapes, and pinna → Incorrect because the pinna (outer ear) is not an ossicle.
- (d) Are tiny muscles providing mechanical force to dampen sound → Incorrect because the ossicles are bones, not muscles. However, small muscles like the tensor tympani and stapedius do help in dampening excessive sound.
Thus, the correct answer is (b).