Which of the following statements is correct?
A. The space within cochlea called scala media is filled with endolymph.
B. The vestibular apparatus is composed of two semicircular canals and the otolith organ consisting of the saccule and utricle.
C. The external auditory meatus helps in equalising the pressures on either side of the eardrum.
D. The membranes constituting cochlea, the Reissner's and basilar, divide the surrounding perilymph filled bony labyrinth into an upper scala tympani and a lower scala vestibuli.

Question

Which of the following statements is correct?
A. The space within cochlea called scala media is filled with endolymph.
B. The vestibular apparatus is composed of two semicircular canals and the otolith organ consisting of the saccule and utricle.
C. The external auditory meatus helps in equalising the pressures on either side of the eardrum.
D. The membranes constituting cochlea, the Reissner's and basilar, divide the surrounding perilymph filled bony labyrinth into an upper scala tympani and a lower scala vestibuli.

Vedantu Content Team · Accepted Answer

Hint: The above case questions about the inner ear, its structure and function, which is partly hearing and partly maintenance of balance. The inner ear is composed of bony labyrinth and membranous labyrinth which are further divided into more parts. Complete Step by Step Answer:As shown in the figure below, scala media located between scala vestibuli and scala tympani is filled with endolymph. This fluid helps in maintaining balance in our body.

Image: Internal Structure of EarThe vestibular apparatus is composed of three semicircular canals and two otolith organs consisting of the saccule and utricle. The canals are sensitive to rotational motions while the otolith organs are concerned with linear motions.The external auditory meatus helps in collecting sound waves from pinna and transmits it to the eardrum. The Eustachian tube helps in equalising the pressures on either side of the eardrum.The membranes constituting cochlea, the Reissner's and basilar, divide the surrounding perilymph filled bony labyrinth into an upper scala vestibuli and a lower scala tympani.

Image: Three semi-circular canals and cochleaThus, the correct answer is A: The space within cochlea called scala media is filled with endolymph. Note: Organ of corti located in scala media has sensory structures which makes us able to hear. The scala media is filled with endolymph while scala tympani and scala vestibuli are filled with perilymph. The Eustachian tube is located in the middle ear, connecting it with the pharynx.