Which of the following is the principal function of the bones (ossicles) of the middle ear?
Ans. C. They increase the efficiency of vibration transfer through the middle earThe transfer of energy through the middle ear from the relatively large eardrum to the smaller oval window by the ossicular chain increases the efficiency of the mechanical transduction process. The bones do not support the membrane structures but allow them to move relatively freely. Interference with the ossicular transmission process by external influences (as by the stapedius and tensor tympani muscles) or by disease processes, acts to reduce the vibration transfer efficiency, a change that can be either protective or harmful. The function of the eustachian tube is independent of the ossicles. While the bones themselves are passive, they are essential to the process of sound conduction.
They provide mechanical support for the flexible membranes to which they are attached (i.e., the eardrum and the oval window)
They reduce the amplitude of the vibrations reaching the oval window, protecting it from mechanical damage
They increase the efficiency of vibration transfer through the middle ear
They control the opening of the eustachian tubes and allow pressures to be equalized
Nervous System