IHS Anatomy and Physiology of Hearing 3

Question 1

Which ossicle directly contacts the oval window of the cochlea?

Accepted Answer

Stapes

Answer

The stapes footplate fits into the oval window, transmitting vibrations from the ossicular chain directly into the perilymph of the inner ear.

Question 2

The impedance matching function of the middle ear is primarily achieved by:

Accepted Answer

The ratio of tympanic membrane area to stapes footplate area

Answer

The large tympanic membrane area (approximately 55 mm²) compared to the small stapes footplate (approximately 3.2 mm²) creates a pressure gain that matches air impedance to fluid impedance.

Question 3

The superior semicircular canal detects head movement in which plane?

Accepted Answer

Sagittal (pitch)

Answer

The superior (anterior) semicircular canal is oriented to detect pitch movements (nodding the head forward and backward).

Question 4

What is the resting membrane potential of a healthy inner hair cell?

Accepted Answer

Approximately -60 mV

Answer

Inner hair cells maintain a resting membrane potential of approximately -60 mV, which becomes less negative (depolarizes) when stereocilia deflect toward the tallest bundle.

Question 5

Which structure produces endolymph in the inner ear?

Accepted Answer

Stria vascularis

Answer

The stria vascularis, a highly vascularized tissue lining the lateral wall of the scala media, actively secretes endolymph and maintains its high K⁺ concentration.

IHS - International Hearing Society Practice Test

IHS - International Hearing Society Practice Test

IHS Anatomy and Physiology of Hearing 3