Question

For each of the structures concerned with hearing A–E, select the most appropriate option from the list below. 

1. A centre for auditory reflexes. 

2. Separates scala in the inner ear. 

3. Equalizes middle ear with 

4. Responsible for bony conduction of atmospheric pressure. incoming sound waves. 

5. Important in air conduction of incoming sound waves. 

A. The basilar membrane. 

B. The skull. 

C. The auditory ossicles. 

D. The Eustachian tube. 

E. Inferior colliculi.

Answer 1

A. Option 2 Separates scala in the inner ear. The basilar membrane on which the organ of Corti lies separates the scala media from the scala tympani. 

B. Option 4 Responsible for bony conduction of incoming sound waves. If the middle ear is completely destroyed by disease, some hearing ability remains as sound waves can be conducted through the bone of the skull to the inner ear. 

C. Option 5 Important in air conduction of incoming sound waves. The malleus, incus and stapes form a good lever system to transmit sound waves from the tympanic membrane to the round window without much attenuation. 

D. Option 3 Equalizes middle ear with atmospheric pressure. The Eustachian tube connects the middle ear to the pharynx so that the pressure on either side of the tympanic membrane is about atmospheric. 

E. Option 1 A centre for auditory reflexes. The cochlear nerve carries auditory impulses from the organ of Corti to the inferior colliculi, centres for auditory reflexes.