Physiology

Renal Filtration and Electrolyte Balance Practice Questions

20 free Renal Filtration and Electrolyte Balance 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.

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All Renal Filtration and Electrolyte Balance questions

20 questions
  1. Q1. Which of the following best describes what is filtered at the glomerulus during normal glomerular filtration?
  2. Q2. Which parameter is defined as the volume of plasma filtered into Bowman's capsule per minute and is widely used to assess kidney function?
  3. Q3. What is the approximate normal value of filtration fraction (FF) in a healthy adult?
  4. Q4. Which segment of the nephron reabsorbs the largest proportion of the filtered sodium load under normal conditions?
  5. Q5. Which transporter in the thick ascending limb of the loop of Henle is most critical for reabsorption of sodium, potassium, and chloride?
  6. Q6. Which hormone increases sodium reabsorption and potassium secretion in the distal nephron, thereby affecting electrolyte and volume balance?
  7. Q7. In conditions of dietary potassium depletion, how does the kidney primarily reduce urinary K⁺ excretion?
  8. Q8. Which of the following best describes how the kidneys contribute to acid–base balance?
  9. Q9. If afferent arteriolar constriction occurs (with no change in efferent arteriole), what is the expected effect on GFR and RPF (renal plasma flow)?
  10. Q10. What happens to the sodium reabsorption in the proximal tubule when basolateral Na⁺/K⁺-ATPase is inhibited?
  11. Q11. Which of the following is a major mechanism by which the kidneys regulate extracellular fluid volume and blood pressure via sodium handling?
  12. Q12. A patient with decreased distal sodium delivery to the collecting duct would most likely experience which electrolyte change?
  13. Q13. Which of the following statements about potassium handling by the kidney is correct under normal dietary potassium intake?
  14. Q14. Which principle explains why water follows sodium reabsorption along much of the nephron, helping to concentrate urine and regulate volume?
  15. Q15. Which nephron segment is impermeable to water but actively reabsorbs ions, contributing to the counter-current multiplier system and concentrating the medullar…
  16. Q16. Which of the following would most likely decrease glomerular filtration rate (GFR)?
  17. Q17. Under conditions of volume depletion, activation of the renin–angiotensin–aldosterone system (RAAS) will have which effect on the nephron?
  18. Q18. Which function is NOT primarily a role of the kidneys in renal physiology and electrolyte balance?
  19. Q19. Which statement best describes the importance of hormonal control (e.g., ADH, aldosterone) over simple filtration in maintaining long-term electrolyte and flui…
  20. Q20. Which of the following correctly explains how the kidney conserves potassium when dietary potassium is low?