Question

Choose the membrane from option below which separates scala media and scala tympani of cochlea.
A. Reissner’s membrane
B. Tectorial membrane
C. Basilar membrane
D. Tympanic membrane

Answer 1

Hint: The ear has three parts: External ear, middle ear and inner ear. The inner ear has a coiled part called cochlea (Labyrinth) and Auditory nerve.

Complete Answer:
Let us analyse the options and find the correct answer.
Option A: The inner ear consists of bony labyrinth and membranous labyrinth. Bony labyrinth is a cavity filled with perilymph and membranous labyrinth consists of cochlea - organ of hearing and Vestibular apparatus - organ of equilibrium.
Cochlea is a coiled structure having 3 canals - upper scala vestibuli, middle scala media and lower scala tympani. Scala vestibuli and Scala media are separated by Reissner’s membrane. Therefore, this is the correct option.

Option B: The tectorial membrane is one of two acellular membranes in the cochlea of the inner ear. The tips of outer hair cells are attached to the tectorial membrane directly. Therefore, this is the incorrect option.

Option C: Basilar membrane is a stiff structural element present inside the cochlea of the inner ear. It separates two liquid-filled tubes which run along the coil of the cochlea, the scala media and the scala tympani. Therefore, this is the incorrect option.

Option D: The tympanic membrane is also called the eardrum. It is present as a separation between the outer and the middle ear. Therefore, this is the incorrect option.

Thus, the correct option is A) Reissner’s membrane.

Note: The normal range of hearing is 20-20,000 Hz. Humans use their ears to hear. The ear generally picks up the sound waves and vibrations present in the environment, but is able to hear only those frequencies which are between 20 - 20,000 Hz.