Functions of urinary tract MCQs With Answer

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Mastering the functions of the urinary tract is essential for B.Pharm students studying renal physiology and renal pharmacology. This concise guide features functions of urinary tract MCQs with answer to reinforce core concepts such as glomerular filtration, tubular reabsorption, secretion, countercurrent exchange, acid–base balance, and urine concentration. Carefully curated for pharmacy undergraduates, the questions emphasize clinical relevance, drug effects on renal function, and mechanisms of diuretics. Ideal for revision before pharmacology, pathophysiology, and therapeutics exams, these MCQs include questions on urine formation, electrolyte handling, blood pressure regulation, and renal drug interactions to deepen understanding. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which structure is the primary site of glomerular filtration in the kidney?

  • Proximal convoluted tubule
  • Glomerulus (renal corpuscle)
  • Loop of Henle
  • Distal convoluted tubule

Correct Answer: Glomerulus (renal corpuscle)

Q2. What is the main force that drives plasma filtration across the glomerular capillary wall?

  • Bowman’s capsule hydrostatic pressure
  • Glomerular capillary oncotic pressure
  • Glomerular capillary hydrostatic pressure
  • Tubular fluid osmotic pressure

Correct Answer: Glomerular capillary hydrostatic pressure

Q3. Which of the following is the best endogenous marker for estimating glomerular filtration rate (GFR)?

  • Plasma albumin
  • Serum creatinine
  • Blood urea nitrogen (BUN)
  • Urinary glucose

Correct Answer: Serum creatinine

Q4. Renal clearance of para-aminohippuric acid (PAH) is used clinically to estimate:

  • Glomerular filtration rate (GFR)
  • Effective renal plasma flow (ERPF)
  • Tubular reabsorption capacity
  • Plasma osmolarity

Correct Answer: Effective renal plasma flow (ERPF)

Q5. Which segment of the nephron is responsible for bulk reabsorption of filtered sodium, water, and bicarbonate?

  • Proximal convoluted tubule (PCT)
  • Thin descending limb
  • Distal convoluted tubule (DCT)
  • Collecting duct

Correct Answer: Proximal convoluted tubule (PCT)

Q6. The countercurrent multiplier mechanism that concentrates urine primarily depends on which nephron segment?

  • Proximal convoluted tubule
  • Loop of Henle
  • Distal convoluted tubule
  • Glomerulus

Correct Answer: Loop of Henle

Q7. Which hormone increases water permeability of the collecting duct by inserting aquaporin-2 channels?

  • Aldosterone
  • Parathyroid hormone
  • Antidiuretic hormone (ADH, vasopressin)
  • Atrial natriuretic peptide (ANP)

Correct Answer: Antidiuretic hormone (ADH, vasopressin)

Q8. Aldosterone primarily acts on which cells to increase sodium reabsorption and potassium secretion?

  • Proximal tubule epithelial cells
  • Principal cells of the cortical collecting duct
  • Intercalated cells of the collecting duct
  • Mesangial cells in the glomerulus

Correct Answer: Principal cells of the cortical collecting duct

Q9. Loop diuretics (e.g., furosemide) inhibit which transporter in the thick ascending limb?

  • SGLT2 cotransporter
  • Na+-K+-2Cl- (NKCC2) cotransporter
  • Na+/Cl- cotransporter (NCC)
  • ENaC sodium channel

Correct Answer: Na+-K+-2Cl- (NKCC2) cotransporter

Q10. Thiazide diuretics primarily inhibit sodium reabsorption in which part of the nephron?

  • Proximal convoluted tubule
  • Thick ascending limb
  • Distal convoluted tubule
  • Collecting duct

Correct Answer: Distal convoluted tubule

Q11. Which clinical condition is characterized by decreased GFR, elevated serum creatinine, and sodium retention?

  • Chronic obstructive pulmonary disease
  • Acute kidney injury (AKI)
  • Hyperthyroidism
  • Diabetes insipidus

Correct Answer: Acute kidney injury (AKI)

Q12. The renal mechanism that adjusts urinary H+ secretion and bicarbonate reabsorption primarily involves which nephron cells?

  • Principal cells
  • Intercalated cells
  • Mesangial cells
  • Juxtaglomerular cells

Correct Answer: Intercalated cells

Q13. Which parameter increases renin secretion from juxtaglomerular cells?

  • Increased renal perfusion pressure
  • Decreased sympathetic stimulation
  • Decreased afferent arteriole stretch
  • High sodium delivery to macula densa

Correct Answer: Decreased afferent arteriole stretch

Q14. Angiotensin II exerts which direct effect on renal hemodynamics?

  • Dilates efferent arteriole
  • Constricts efferent arteriole more than afferent
  • Decreases aldosterone secretion
  • Inhibits sodium reabsorption in PCT

Correct Answer: Constricts efferent arteriole more than afferent

Q15. Which of the following drugs reduces intraglomerular pressure by preferentially dilating the efferent arteriole?

  • Ace inhibitor (e.g., lisinopril)
  • Loop diuretic (e.g., bumetanide)
  • Thiazide diuretic (e.g., hydrochlorothiazide)
  • Beta blocker (e.g., metoprolol)

Correct Answer: Ace inhibitor (e.g., lisinopril)

Q16. The thin descending limb of Henle is highly permeable to which substance?

  • Sodium and chloride
  • Urea
  • Water
  • Glucose

Correct Answer: Water

Q17. Which tubular transporter is inhibited by SGLT2 inhibitors used in diabetes therapy?

  • Glucose transporter in PCT (SGLT2)
  • Na+-K+-2Cl- cotransporter
  • Na+/H+ exchanger in collecting duct
  • ENaC channel

Correct Answer: Glucose transporter in PCT (SGLT2)

Q18. Renal handling of potassium: which condition increases potassium secretion in the cortical collecting duct?

  • Low aldosterone levels
  • High dietary potassium intake
  • Low tubular flow rate
  • Hypokalemia

Correct Answer: High dietary potassium intake

Q19. Which urinary finding is most characteristic of nephrotic syndrome?

  • Hematuria with red cell casts
  • Heavy proteinuria and hypoalbuminemia
  • Low urine protein and hyperkalemia
  • High specific gravity without proteinuria

Correct Answer: Heavy proteinuria and hypoalbuminemia

Q20. Clearance of inulin is used experimentally to measure which renal function?

  • Renal plasma flow (RPF)
  • Glomerular filtration rate (GFR)
  • Tubular secretion rate
  • Renal blood pressure

Correct Answer: Glomerular filtration rate (GFR)

Q21. Which transporter in the proximal tubule is responsible for the majority of bicarbonate reclamation?

  • Na+/K+ ATPase
  • SGLT1 glucose transporter
  • Na+/H+ exchanger (NHE3)
  • NKCC2 cotransporter

Correct Answer: Na+/H+ exchanger (NHE3)

Q22. A defect in proximal tubular reabsorption of amino acids, glucose, bicarbonate, and phosphate suggests which syndrome?

  • Bartter syndrome
  • Gitelman syndrome
  • Fanconi syndrome
  • Nephrotic syndrome

Correct Answer: Fanconi syndrome

Q23. Which condition produces dilute urine with low urine osmolality and polyuria due to decreased ADH effect?

  • SIADH
  • Nephrogenic diabetes insipidus
  • Hyperaldosteronism
  • Acute tubular necrosis

Correct Answer: Nephrogenic diabetes insipidus

Q24. SIADH leads to which characteristic laboratory finding?

  • Hypernatremia due to water loss
  • Hyponatremia with concentrated urine
  • Metabolic acidosis with low bicarbonate
  • Hypokalemia with polyuria

Correct Answer: Hyponatremia with concentrated urine

Q25. The macula densa senses which lumen parameter to modulate tubuloglomerular feedback?

  • Glucose concentration
  • Sodium chloride concentration
  • Urine pH
  • Protein concentration

Correct Answer: Sodium chloride concentration

Q26. Which electrolyte disturbance commonly occurs with loop diuretic therapy?

  • Hyperkalemia
  • Hypokalemia
  • Hypercalcemia
  • Hypermagnesemia

Correct Answer: Hypokalemia

Q27. Which inherited disorder mimics chronic loop diuretic use and presents with metabolic alkalosis and hypokalemia?

  • Gitelman syndrome
  • Bartter syndrome
  • Alport syndrome
  • Goodpasture syndrome

Correct Answer: Bartter syndrome

Q28. Which of the following increases urinary excretion of sodium and leads to natriuresis?

  • Aldosterone
  • Antidiuretic hormone
  • Atrial natriuretic peptide (ANP)
  • Renin

Correct Answer: Atrial natriuretic peptide (ANP)

Q29. Organic anion transporters (OATs) in the proximal tubule are important for secretion of which class of drugs?

  • Beta blockers
  • Penicillins and NSAIDs
  • Loop diuretics only
  • Insulin

Correct Answer: Penicillins and NSAIDs

Q30. Which parameter best describes a kidney’s ability to clear a substance from plasma per unit time?

  • GFR
  • Renal clearance
  • Renal perfusion pressure
  • Filtration fraction

Correct Answer: Renal clearance

Q31. Filtration fraction is defined as the ratio of:

  • GFR to renal plasma flow (RPF)
  • RPF to GFR
  • Urine output to GFR
  • Kidney size to body weight

Correct Answer: GFR to renal plasma flow (RPF)

Q32. Which drug class can reduce renal prostaglandin synthesis and potentially precipitate renal ischemia in hypovolemic patients?

  • ACE inhibitors
  • NSAIDs
  • Loop diuretics
  • Calcium channel blockers

Correct Answer: NSAIDs

Q33. Which urinary constituent appears in high amounts during rhabdomyolysis and can cause acute tubular necrosis?

  • Glucose
  • Myoglobin
  • Albumin
  • Cholesterol

Correct Answer: Myoglobin

Q34. The micturition reflex is primarily coordinated by which nervous system center?

  • Medulla oblongata
  • Pontine micturition center
  • Cerebellum
  • Basal ganglia

Correct Answer: Pontine micturition center

Q35. Which ion is reabsorbed in the thick ascending limb by an electroneutral mechanism and contributes to urine dilution?

  • Calcium
  • Bicarbonate
  • Sodium and chloride
  • Potassium only

Correct Answer: Sodium and chloride

Q36. Which test provides a rapid bedside estimate of renal concentrating ability?

  • Serum creatinine
  • Urine specific gravity
  • Plasma renin activity
  • Fractional excretion of sodium (FENa)

Correct Answer: Urine specific gravity

Q37. In prerenal azotemia, what is the typical fractional excretion of sodium (FENa)?

  • High (>2%)
  • Low (<1%)
  • Exactly 1.5%
  • Variable and not useful

Correct Answer: Low (<1%)

Q38. Which of the following is the primary mechanism of potassium-sparing diuretics like spironolactone?

  • Inhibition of NKCC2 in TAL
  • Sodium channel blockade in the collecting duct or aldosterone receptor antagonism
  • Inhibition of carbonic anhydrase in PCT
  • Blockade of SGLT2 in PCT

Correct Answer: Sodium channel blockade in the collecting duct or aldosterone receptor antagonism

Q39. Which renal change is expected after ACE inhibitor therapy in a patient with renal artery stenosis?

  • Increase in GFR due to increased glomerular pressure
  • Decreased GFR due to loss of efferent arteriole constriction
  • Marked hypokalemia
  • Increased proximal tubular reabsorption of bicarbonate

Correct Answer: Decreased GFR due to loss of efferent arteriole constriction

Q40. Proteinuria with hyperlipidemia and hypoalbuminemia suggests which renal pathology?

  • Nephritic syndrome
  • Nephrotic syndrome
  • Acute interstitial nephritis
  • Pyelonephritis

Correct Answer: Nephrotic syndrome

Q41. Which substance is freely filtered, neither secreted nor reabsorbed, and therefore useful for measuring GFR experimentally?

  • Creatinine
  • Inulin
  • PAH
  • Albumin

Correct Answer: Inulin

Q42. Which mechanism explains why loop diuretics can cause metabolic alkalosis?

  • Inhibition of carbonic anhydrase in PCT
  • Volume contraction leading to increased bicarbonate reabsorption and aldosterone-mediated H+ secretion
  • Direct increase in renal H+ secretion via ENaC activation
  • Inhibition of distal HCO3- secretion

Correct Answer: Volume contraction leading to increased bicarbonate reabsorption and aldosterone-mediated H+ secretion

Q43. Which condition is most likely to cause an elevated blood urea nitrogen (BUN) to creatinine ratio (>20:1)?

  • Intrinsic renal failure
  • Prerenal azotemia (e.g., dehydration)
  • Postrenal obstruction only
  • Hepatic failure

Correct Answer: Prerenal azotemia (e.g., dehydration)

Q44. Which renal structure generates prostaglandins that dilate the afferent arteriole under stress?

  • Mesangial cells
  • Juxtaglomerular apparatus
  • Renal tubular epithelial cells
  • Podocytes

Correct Answer: Renal tubular epithelial cells

Q45. Which drug class can cause hyperkalemia by reducing aldosterone synthesis or action?

  • ACE inhibitors and potassium-sparing diuretics
  • Loop diuretics
  • Thiazides
  • SGLT2 inhibitors

Correct Answer: ACE inhibitors and potassium-sparing diuretics

Q46. The main role of urea recycling in the inner medulla is to:

  • Prevent water reabsorption in the collecting duct
  • Facilitate urine concentration by increasing medullary osmolarity
  • Enhance bicarbonate secretion
  • Promote sodium excretion

Correct Answer: Facilitate urine concentration by increasing medullary osmolarity

Q47. Which laboratory test is most sensitive for early detection of decreased renal function?

  • Serum urea alone
  • Serum creatinine and estimated GFR
  • Urine glucose
  • Serum sodium

Correct Answer: Serum creatinine and estimated GFR

Q48. Which tubular segment is primarily responsible for calcium reabsorption influenced by PTH?

  • Proximal convoluted tubule
  • Thick ascending limb and distal convoluted tubule
  • Collecting duct
  • Thin descending limb

Correct Answer: Thick ascending limb and distal convoluted tubule

Q49. In acute tubular necrosis (ATN), which urinary sediment finding is typical?

  • Fatty casts
  • RBC casts
  • Granular (muddy brown) casts
  • Waxy casts only

Correct Answer: Granular (muddy brown) casts

Q50. Which of the following best explains how NSAIDs can reduce renal blood flow in susceptible patients?

  • Inhibition of renin release leading to efferent arteriole vasodilation
  • Blockade of prostaglandin synthesis leading to afferent arteriole vasoconstriction
  • Direct inhibition of Na+/K+ ATPase in PCT
  • Stimulation of ADH release causing vasoconstriction

Correct Answer: Blockade of prostaglandin synthesis leading to afferent arteriole vasoconstriction

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