Question

Scala media is
A. Chamber which is related to perilymph
B. Cochlear canal
C. Chamber of semicircular canal
D. None of the above

Answer 1

Scala media is situated between the tympanic duct and the vestibular duct, separated respectively by the basilar membrane and Reissner’s membrane. It is located in the hearing part of the inner ear that forms a spiral structure that makes it resemble a snail.

Complete answer:
Option (A) is incorrect. Scala vestibuli or the vestibular duct is a chamber that contains perilymph. It is one of the three scalar chambers that lies superior to the cochlear duct and next to the oval window.
Option (B) is correct. Scala media is a cochlear canal that contains endolymph and it is a region of high potassium ion concentration that is located between the scala vestibuli and the scala tympani in the cochlea.
Option (C) is incorrect. The inner ear can be thought of as two organs i.e., semicircular canals and the cochlea. The semicircular canals serve as the body’s balancing organ while the cochlea serves as the body’s microphone. Thus, scala media is a cochlear canal and not the chamber of the semicircular canal.
Option (D) is incorrect. As option (B) i.e., the cochlear canal is correct therefore, “none of the above options” cannot be correct.

Hence, the correct answer is option (B).

Note: The cochlear canal or scala media is a part of the cochlea that is known for converting the sound pressure impulses into electrical impulses that are passed on to the brain through the auditory nerve. There are three functional regions in and around the scala media i.e., the organ of Corti, spiral ganglion, and stria vascularis.