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Gastric Acid pH — FRCA Primary MCQ

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HardPhysiology - Gastrointestinal & HepaticGastric Acid pHFRCA Primary

What is the usual pH range of fasting gastric juice in a healthy adult?

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Correct answer: A1–2, produced by active parietal-cell hydrogen secretion

The best answer is “1–2, produced by active parietal-cell hydrogen secretion”. Fasting gastric juice is strongly acidic, commonly around pH 1–2, through hydrochloric-acid secretion by parietal cells via the H+/K+-ATPase. Gastric pH rises after meals and with acid-suppressing drugs, so the value is a fasting physiological reference rather than a fixed value throughout the day.

Reference: Royal College of Anaesthetists, Primary FRCA Syllabus 2021: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf