Gastrointestinal: hepatic zonation and ischaemia: 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.

Try it

Physiology · Gastrointestinal: hepatic zonation and ischaemia

Sample item

A patient who survived prolonged hypotension has liver biopsy showing necrosis of hepatocytes around the central veins, with sparing of the periportal cells. Why are these cells most vulnerable?

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

The answer and the reasoning

A. They are at the end of the sinusoidal blood flow, where oxygen tension is lowest

In the hepatic acinus, blood from the portal vein and hepatic artery flows through the sinusoids from the periportal zone 1 to the centrilobular zone 3. Oxygen is extracted along the way, so zone 3 hepatocytes receive the least oxygen and are the first to die in ischaemia (shock liver).

Option by option

  • A. They are at the end of the sinusoidal blood flow, where oxygen tension is lowest (correct)

    Correct. Zone 3 receives blood last, with the lowest oxygen tension.

  • B. They have the lowest metabolic activity

    Zone 3 hepatocytes are metabolically very active, including drug metabolism, and not inactive.

  • C. They receive the highest oxygen tension from the hepatic artery

    The hepatic arterial and portal blood enter at the periportal zone, which has the highest oxygen tension.

  • D. They are exposed to the highest portal vein pressure

    Portal and arterial blood mix at the periportal end, so the oxygen supply is highest there, not at the central vein.

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 Physiology questions

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is A, They are at the end of the sinusoidal blood flow, where oxygen tension is lowest. In the hepatic acinus, blood from the portal vein and hepatic artery flows through the sinusoids from the periportal zone 1 to the centrilobular zone 3.

Why is "They have the lowest metabolic activity" not the answer?

Zone 3 hepatocytes are metabolically very active, including drug metabolism, and not inactive.

Why is "They receive the highest oxygen tension from the hepatic artery" not the answer?

The hepatic arterial and portal blood enter at the periportal zone, which has the highest oxygen tension.

Why is "They are exposed to the highest portal vein pressure" not the answer?

Portal and arterial blood mix at the periportal end, so the oxygen supply is highest there, not at the central vein.

What concept does this question test?

It tests Gastrointestinal: hepatic zonation and ischaemia in Physiology. Oxygen is extracted along the way, so zone 3 hepatocytes receive the least oxygen and are the first to die in ischaemia (shock liver).

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 Gastrointestinal: hepatic zonation and ischaemia?

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.