Respiratory system: cough reflex: 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 · Respiratory system: cough reflex

Sample item

A patient with an aspiration episode coughs forcefully. Which sequence describes the central part of the cough?

ADeep expiration, glottic opening, then forced inspirationBDeep inspiration, glottic closure with forced expiratory effort, then sudden opening of the glottisCShallow inspiration, glottis kept open, then forced expirationDGlottic closure with relaxation of the expiratory muscles

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

The answer and the reasoning

B. Deep inspiration, glottic closure with forced expiratory effort, then sudden opening of the glottis

A cough begins with a deep inspiration, followed by closure of the glottis and contraction of the expiratory muscles, which raises intrathoracic pressure markedly. Sudden opening of the glottis then produces an explosive expiratory flow that clears the airway.

Option by option

A. Deep expiration, glottic opening, then forced inspiration
A cough involves a deep inspiration first, followed by forced expiration, not the reverse.
B. Deep inspiration, glottic closure with forced expiratory effort, then sudden opening of the glottis (correct)
Correct. Pressure builds against the closed glottis before it is suddenly released.
C. Shallow inspiration, glottis kept open, then forced expiration
Without glottic closure, pressure cannot build to an explosive level.
D. Glottic closure with relaxation of the expiratory muscles
Relaxed expiratory muscles cannot raise intrathoracic pressure.

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 B, Deep inspiration, glottic closure with forced expiratory effort, then sudden opening of the glottis. A cough begins with a deep inspiration, followed by closure of the glottis and contraction of the expiratory muscles, which raises intrathoracic pressure markedly.

Why is "Deep expiration, glottic opening, then forced inspiration" not the answer?

A cough involves a deep inspiration first, followed by forced expiration, not the reverse.

Why is "Shallow inspiration, glottis kept open, then forced expiration" not the answer?

Without glottic closure, pressure cannot build to an explosive level.

Why is "Glottic closure with relaxation of the expiratory muscles" not the answer?

Relaxed expiratory muscles cannot raise intrathoracic pressure.

What concept does this question test?

It tests Respiratory system: cough reflex in Physiology. Sudden opening of the glottis then produces an explosive expiratory flow that clears the airway.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Respiratory system: cough reflex?

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.