Acid-base homeostasis Practice Questions
19 free Acid-base homeostasis practice questions for the USMLE Step 1, each with the correct answer and a detailed explanation. Open any question below, or take the full set as an interactive quiz.
Questions
19 questions
All Acid-base homeostasis questions
- Q1. What is the normal physiological arterial blood pH range maintained by acid–base homeostasis in humans?
- Q2. Which buffer system acts as the principal extracellular (plasma) buffer against acid–base disturbances in the body?
- Q3. According to acid–base physiology, if bicarbonate concentration increases or PaCO₂ decreases, what happens to blood pH (assuming other factors constant)?
- Q4. Which organ is primarily responsible for long-term (hours to days) regulation of acid–base balance by modifying bicarbonate reabsorption and hydrogen ion excre…
- Q5. Which part of the nephron reabsorbs approximately 70–80% of filtered bicarbonate under normal conditions?
- Q6. What compensatory mechanism does the respiratory system provide in response to a primary metabolic acidosis?
- Q7. Which of the following is the fastest acting mechanism to buffer acute changes in blood pH?
- Q8. In metabolic alkalosis, which renal adaptation helps restore normal pH over time?
- Q9. What is the major non-volatile acid elimination pathway in kidneys during chronic acid loads (e.g., metabolic acidosis)?
- Q10. Which condition describes a primary respiratory alkalosis on arterial blood gas analysis?
- Q11. Which acid–base disturbance is most likely in a patient with prolonged vomiting (gastric acid loss)?
- Q12. Why is the bicarbonate buffer system considered “open” in human physiology?
- Q13. What happens to intracellular hydrogen ion concentration when extracellular pH drops (acidemia), if buffers and cellular mechanisms cannot fully compensate?
- Q14. In chronic respiratory acidosis, what renal adaptation helps mitigate the acid load over days?
- Q15. Which intracellular buffer system contributes significantly to pH regulation inside cells?
- Q16. Which of the following best describes metabolic acidosis on arterial blood gas analysis?
- Q17. Why are small changes in plasma H⁺ concentration physiologically significant even though absolute H⁺ concentration is tiny (≈ 40 nmol/L)?
- Q18. Which of the following represents a primary disturbance in respiratory acidosis?
- Q19. Which renal tubular cell type is primarily responsible for H⁺ secretion during chronic acid–base regulation?