Question

In mammalian cochlea, the thin-walled sloping roof of the scala media is referred to as:
A. Organ of Corti
B. Scala tympani
C. Basilar membrane
D. Reissner's membrane

Answer 1

Hint: Our ear is divided into three parts:- outer ear ( which consists of pinna and canal), middle ear(malleus, incus and stapes) and inner ear which consists of cochlea. The inner ear is filled with a fluid called labyrinth which is subdivided into bony and membranous labyrinth. A series of channels are present which constitute the bony labyrinth and the membranous labyrinth lies inside these channels. The membranous labyrinth is surrounded by a fluid called perilymph and is filled with a fluid called endolymph. The coiled part of the labyrinth which is lined by certain hair cells is called cochlea.

Complete Step by Step Answer:
The Reissner's and basilar membrane constitutes the cochlea. These membranes divide the bony labyrinth into scala vestibuli and scala tympani. Scala media is the space within the cochlea which is filled with endolymph which is secreted by its lining of epithelial cells. Reissner's membrane acts as a diffusion barrier that allows the nutrients to travel from the perilymph to the endolymph of the membranous labyrinth. So, in the mammalian cochlea reissner's membrane is referred to as the thin-walled sloping roof of the scala media. A structure called the organ of corti is present at the basilar membrane which contains certain hair cells that act as auditory receptors.

Thus, the correct answer is option D:- Reissner's membrane.


Note: Cochlea is a very important part of our ear and any damage to it will cause permanent hearing loss. The cochlea is lined by hair cells which cannot regenerate. The cells of the inner ear and cochlea can be damaged by loud noise.