Thermoregulation: 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 · Thermoregulation

Sample item

A 4-year-old with a bacterial infection has a temperature of 39 degrees C. At the onset she shivered and had cold hands. What is the basic mechanism of her fever?

AUpward resetting of the hypothalamic set point by prostaglandin E2BDirect heat production by bacterial toxins in skeletal muscleCHeat gain from the environment overwhelming heat lossDFailure of sweat glands to secrete

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

The answer and the reasoning

A. Upward resetting of the hypothalamic set point by prostaglandin E2

Endogenous pyrogens such as interleukin-1 stimulate prostaglandin E2 production in the hypothalamus, which raises the set point. The body then feels cold relative to the new target, causing shivering and vasoconstriction until the temperature reaches it. Antipyretics such as paracetamol work by reducing prostaglandin synthesis.

Option by option

A. Upward resetting of the hypothalamic set point by prostaglandin E2 (correct)
Correct. A raised set point explains the initial shivering and cold peripheries.
B. Direct heat production by bacterial toxins in skeletal muscle
Toxins act mainly by releasing cytokines, not by directly heating muscle.
C. Heat gain from the environment overwhelming heat loss
That describes hyperthermia such as heat stroke, in which the set point stays normal.
D. Failure of sweat glands to secrete
Anhidrosis can cause hyperthermia in hot conditions but does not explain the cold, shivering onset.

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 A, Upward resetting of the hypothalamic set point by prostaglandin E2. Endogenous pyrogens such as interleukin-1 stimulate prostaglandin E2 production in the hypothalamus, which raises the set point.

Why is "Direct heat production by bacterial toxins in skeletal muscle" not the answer?

Toxins act mainly by releasing cytokines, not by directly heating muscle.

Why is "Heat gain from the environment overwhelming heat loss" not the answer?

That describes hyperthermia such as heat stroke, in which the set point stays normal.

Why is "Failure of sweat glands to secrete" not the answer?

Anhidrosis can cause hyperthermia in hot conditions but does not explain the cold, shivering onset.

What concept does this question test?

It tests Thermoregulation in Physiology. The body then feels cold relative to the new target, causing shivering and vasoconstriction until the temperature reaches it. Antipyretics such as paracetamol work by reducing prostaglandin synthesis.

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 Thermoregulation?

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.