Gastrointestinal physiology: enteropeptidase: 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 · Gastrointestinal physiology: enteropeptidase

Sample item

An infant has failure to thrive, diarrhoea and hypoproteinaemic oedema from weaning. Duodenal fluid has trypsinogen but almost no trypsin or chymotrypsin activity, and adding enteropeptidase restores activity. Which defect is present?

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

The answer and the reasoning

D. Deficiency of duodenal brush-border enteropeptidase, so trypsinogen is not activated

Enteropeptidase on the duodenal brush border converts trypsinogen to trypsin, which then activates the other pancreatic proenzymes. Its absence produces protein malabsorption with hypoproteinaemia, diarrhoea and failure to thrive despite a structurally normal pancreas.

Option by option

  • A. Absence of pancreatic lipase only

    Isolated lipase deficiency causes steatorrhoea but not impaired protein digestion.

  • B. Defective chloride channel (CFTR) in pancreatic ducts

    CFTR defects cause thick secretions and are not corrected by adding enteropeptidase.

  • C. Absence of pancreatic secretory trypsin inhibitor

    Loss of the trypsin inhibitor causes premature activation and pancreatitis.

  • D. Deficiency of duodenal brush-border enteropeptidase, so trypsinogen is not activated (correct)

    Correct. Without enteropeptidase, trypsin and downstream enzymes remain inactive.

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.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is D, Deficiency of duodenal brush-border enteropeptidase, so trypsinogen is not activated. Enteropeptidase on the duodenal brush border converts trypsinogen to trypsin, which then activates the other pancreatic proenzymes.

Why is "Absence of pancreatic lipase only" not the answer?

Isolated lipase deficiency causes steatorrhoea but not impaired protein digestion.

Why is "Defective chloride channel (CFTR) in pancreatic ducts" not the answer?

CFTR defects cause thick secretions and are not corrected by adding enteropeptidase.

Why is "Absence of pancreatic secretory trypsin inhibitor" not the answer?

Loss of the trypsin inhibitor causes premature activation and pancreatitis.

What concept does this question test?

It tests Gastrointestinal physiology: enteropeptidase in Physiology. Its absence produces protein malabsorption with hypoproteinaemia, diarrhoea and failure to thrive despite a structurally normal pancreas.

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 physiology: enteropeptidase?

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.