Special senses: semicircular canals: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Special senses: semicircular canals

Sample item

A volunteer is rotated in a chair at constant speed with eyes closed for one minute and then stopped abruptly. She feels she is rotating in the opposite direction and shows nystagmus. What explains this?

AThe canals detect constant velocity and keep firing during the spinBThe otolith organs are stimulated by the sudden loss of linear accelerationCHair cells in the cochlea respond to the change in speedDEndolymph keeps moving after the sudden stop, deflecting the cupula and signalling angular deceleration

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Endolymph keeps moving after the sudden stop, deflecting the cupula and signalling angular deceleration

The semicircular canals detect angular acceleration and deceleration through endolymph inertia moving the cupula. During constant rotation the endolymph catches up and the signal fades, but abrupt stopping makes the endolymph continue to move and deflect the cupula in the opposite sense. The result is a false sensation of opposite rotation with nystagmus.

Option by option

A. The canals detect constant velocity and keep firing during the spin
Canals respond to changes in angular velocity and fall silent in constant rotation.
B. The otolith organs are stimulated by the sudden loss of linear acceleration
Otolith organs detect linear acceleration and head tilt rather than rotation.
C. Hair cells in the cochlea respond to the change in speed
The cochlea is concerned with hearing and does not detect rotation.
D. Endolymph keeps moving after the sudden stop, deflecting the cupula and signalling angular deceleration (correct)
Correct. Endolymph inertia on deceleration deflects the cupula.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is D, Endolymph keeps moving after the sudden stop, deflecting the cupula and signalling angular deceleration. The semicircular canals detect angular acceleration and deceleration through endolymph inertia moving the cupula.

Why is "The canals detect constant velocity and keep firing during the spin" not the answer?

Canals respond to changes in angular velocity and fall silent in constant rotation.

Why is "The otolith organs are stimulated by the sudden loss of linear accele…" not the answer?

Otolith organs detect linear acceleration and head tilt rather than rotation.

Why is "Hair cells in the cochlea respond to the change in speed" not the answer?

The cochlea is concerned with hearing and does not detect rotation.

What concept does this question test?

It tests Special senses: semicircular canals in Physiology. During constant rotation the endolymph catches up and the signal fades, but abrupt stopping makes the endolymph continue to move and deflect the cupula in the opposite sense. The result is a false sensation of opposite rotation with nystagmus.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Special senses: semicircular canals?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.