Adaptation: atrophy: practice question

A Pathology 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.

Try it

Pathology · Adaptation: atrophy

Sample item

A 30-year-old man has his leg in plaster for 8 weeks after a tibial fracture. The thigh circumference is reduced, but strength recovers with physiotherapy. What is the main mechanism of the muscle wasting?

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

The answer and the reasoning

B. Reduced protein synthesis with increased degradation through the ubiquitin-proteasome pathway

Disuse atrophy is an adaptive decrease in cell size caused by decreased protein synthesis and increased proteolysis, mainly through the ubiquitin-proteasome pathway, with some contribution from autophagy. Because the fibres are shrunken but alive, atrophy is reversible when load is restored. Denervation atrophy is a separate cause.

Option by option

  • A. Coagulative necrosis of whole muscle fibres with fibrous replacement

    Necrosis with fibrosis would be irreversible and would not recover with physiotherapy.

  • B. Reduced protein synthesis with increased degradation through the ubiquitin-proteasome pathway (correct)

    Correct. Tilting the balance towards proteolysis shrinks the cells reversibly.

  • C. Apoptotic loss of motor neurons from the anterior horn

    Motor neuron loss causes denervation atrophy, which is not the reason after plaster immobilisation.

  • D. Hyperplasia of fat cells within the muscle bundles

    Fat infiltration may occur in chronic disorders but is not the primary mechanism of disuse atrophy.

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.

More Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is B, Reduced protein synthesis with increased degradation through the ubiquitin-proteasome pathway. Disuse atrophy is an adaptive decrease in cell size caused by decreased protein synthesis and increased proteolysis, mainly through the ubiquitin-proteasome pathway, with some contribution from autophagy.

Why is "Coagulative necrosis of whole muscle fibres with fibrous replacement" not the answer?

Necrosis with fibrosis would be irreversible and would not recover with physiotherapy.

Why is "Apoptotic loss of motor neurons from the anterior horn" not the answer?

Motor neuron loss causes denervation atrophy, which is not the reason after plaster immobilisation.

Why is "Hyperplasia of fat cells within the muscle bundles" not the answer?

Fat infiltration may occur in chronic disorders but is not the primary mechanism of disuse atrophy.

What concept does this question test?

It tests Adaptation: atrophy in Pathology. Because the fibres are shrunken but alive, atrophy is reversible when load is restored. Denervation atrophy is a separate cause.

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 Adaptation: atrophy?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.