Question

what structure is highlighted?

a. inner phalangeal cells
b. basilar membrane
c. inner hair cell
d. outer phalangeal cells
e. tectorial membrane

Explanation:

Identify the histological section and highlighted structure

Using the Basilar Membrane Structure knowledge point

• The provided image shows a high-magnification histological section of the organ of Corti within the cochlea of the inner ear.
• A distinct green line highlights the horizontal fibrous layer supporting the sensory epithelium (hair cells and supporting cells).
• This highlighted structure is the basilar membrane, which separates the cochlear duct (scala media) from the scala tympani.

Match with the multiple-choice options

• Option A: Inner phalangeal cells (supporting cells immediately adjacent to the inner hair cell, not highlighted).
• Option B: Basilar membrane (the highlighted green line at the base of the organ of Corti).
• Option C: Inner hair cell (the single sensory cell located on the inner side of the tunnel of Corti, not highlighted).
• Option D: Outer phalangeal cells (Deiters cells supporting the outer hair cells, not highlighted).
• Option E: Tectorial membrane (the gelatinous structure projecting over the hair cells, visible above but not highlighted).
• Therefore, the highlighted structure is the basilar membrane.

Answer:

• (A) Inner phalangeal cells
• (B) Basilar membrane (Correct answer)
• (C) Inner hair cell
• (D) Outer phalangeal cells
• (E) Tectorial membrane