Cell injury and adaptation: ultrastructure of irreversible injury: 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.

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Pathology · Cell injury and adaptation: ultrastructure of irreversible injury

Sample item

Electron microscopy of ischaemic myocardium is examined to decide whether injury has become irreversible. Which finding indicates the point of no return?

AMitochondrial vacuolisation with large amorphous densitiesBBlebs on the plasma membraneCClumping of nuclear chromatinDDetachment of ribosomes from the endoplasmic reticulum

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

The answer and the reasoning

A. Mitochondrial vacuolisation with large amorphous densities

Irreversibility is marked by severe mitochondrial damage, with vacuolisation and amorphous densities, together with extensive membrane damage and rupture of lysosomes. Ribosome detachment, membrane blebs, myelin figures and chromatin clumping can all occur in reversible injury. Leakage of intracellular enzymes such as troponin follows loss of membrane integrity.

Option by option

A. Mitochondrial vacuolisation with large amorphous densities (correct)
Correct. Amorphous mitochondrial densities signal irreversible mitochondrial and membrane damage.
B. Blebs on the plasma membrane
Blebbing is a feature of reversible injury.
C. Clumping of nuclear chromatin
Chromatin clumping can be seen in reversible injury.
D. Detachment of ribosomes from the endoplasmic reticulum
Ribosome detachment occurs early in reversible injury.

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 Pathology question

What is the answer to this Pathology question?

The best answer is A, Mitochondrial vacuolisation with large amorphous densities. Irreversibility is marked by severe mitochondrial damage, with vacuolisation and amorphous densities, together with extensive membrane damage and rupture of lysosomes.

Why is "Blebs on the plasma membrane" not the answer?

Blebbing is a feature of reversible injury.

Why is "Clumping of nuclear chromatin" not the answer?

Chromatin clumping can be seen in reversible injury.

Why is "Detachment of ribosomes from the endoplasmic reticulum" not the answer?

Ribosome detachment occurs early in reversible injury.

What concept does this question test?

It tests Cell injury and adaptation: ultrastructure of irreversible injury in Pathology. Ribosome detachment, membrane blebs, myelin figures and chromatin clumping can all occur in reversible injury. Leakage of intracellular enzymes such as troponin follows loss of membrane integrity.

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 Cell injury and adaptation: ultrastructure of irreversible injury?

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.