Physiology of urine formation MCQs With Answer

Physiology of urine formation MCQs With Answer is an essential resource for B. Pharm students preparing for exams in renal physiology and pharmacology. This concise, keyword-rich introduction focuses on core processes—glomerular filtration, tubular reabsorption, tubular secretion, countercurrent multiplier, and hormonal regulation by ADH and aldosterone—while linking clinical and drug-related implications like diuretics, ACE inhibitors, and renal clearance methods (inulin, PAH). Clear explanations and targeted practice questions enhance understanding of transport mechanisms, acid-base balance, and nephron segment functions. Ideal for revision and applied learning, this set strengthens both theoretical knowledge and pharmacy-relevant problem solving. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary force that drives glomerular filtration?

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

Correct Answer: Glomerular capillary hydrostatic pressure

Q2. Which molecule is considered the gold standard for measuring glomerular filtration rate (GFR)?

• Para-aminohippuric acid (PAH)
• Creatinine
• Inulin
• Urea

Correct Answer: Inulin

Q3. Clearance of which substance approximates renal plasma flow (RPF)?

• Inulin
• Creatinine
• PAH
• Urea

Correct Answer: PAH

Q4. Tubular maximum (Tm) refers to:

• The minimum reabsorption rate of a solute
• The maximum secretion capacity of the nephron
• The maximum reabsorption rate that transporters can achieve
• The rate of passive diffusion across the tubular epithelium

Correct Answer: The maximum reabsorption rate that transporters can achieve

Q5. Which segment of the nephron is impermeable to water but actively reabsorbs NaCl?

• Proximal convoluted tubule
• Thin descending limb of loop of Henle
• Thick ascending limb of loop of Henle
• Collecting duct

Correct Answer: Thick ascending limb of loop of Henle

Q6. ADH (vasopressin) primarily increases water reabsorption by:

• Increasing Na+/K+ ATPase activity in proximal tubule
• Inserting aquaporin-2 channels in collecting duct principal cells
• Opening sodium channels in the loop of Henle
• Stimulating urea secretion in proximal tubule

Correct Answer: Inserting aquaporin-2 channels in collecting duct principal cells

Q7. The countercurrent multiplier system is mainly established by which nephron structures?

• Glomerulus and proximal tubule
• Loop of Henle and vasa recta
• Distal tubule and collecting duct
• Bowman’s capsule and peritubular capillaries

Correct Answer: Loop of Henle and vasa recta

Q8. Which hormone increases sodium reabsorption and potassium secretion in the cortical collecting duct?

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

Correct Answer: Aldosterone

Q9. Which process in the kidney contributes most to acid excretion?

• Reabsorption of filtered bicarbonate
• Secretion of ammonium (NH4+) and titratable acids
• Filtration of hydrogen ions at glomerulus
• Urea recycling in the inner medulla

Correct Answer: Secretion of ammonium (NH4+) and titratable acids

Q10. Which diuretic acts by inhibiting the Na+-K+-2Cl− cotransporter in the thick ascending limb?

• Hydrochlorothiazide
• Furosemide
• Spironolactone
• Amiloride

Correct Answer: Furosemide

Q11. Renal autoregulation of GFR over a range of arterial pressures primarily involves:

• Hormonal control by aldosterone
• Sympathetic nervous system adjustments only
• Myogenic response and tubuloglomerular feedback
• Changes in plasma oncotic pressure

Correct Answer: Myogenic response and tubuloglomerular feedback

Q12. The macula densa senses which parameter to modulate GFR via tubuloglomerular feedback?

• Renal interstitial hydrostatic pressure
• Distal tubular sodium chloride concentration
• Blood pH
• Plasma renin activity

Correct Answer: Distal tubular sodium chloride concentration

Q13. Which transport mechanism predominates for glucose reabsorption in the proximal tubule?

• Paracellular diffusion
• Na+-dependent secondary active transport (SGLT)
• Facilitated diffusion via GLUT on apical membrane
• Active transport via ATP-driven glucose pumps

Correct Answer: Na+-dependent secondary active transport (SGLT)

Q14. If plasma protein concentration decreases, what is the expected effect on glomerular filtration rate (GFR)?

• GFR decreases due to reduced renal blood flow
• GFR increases due to decreased glomerular oncotic pressure
• GFR remains unchanged because filtration fraction is constant
• GFR decreases due to increased Bowman’s capsule pressure

Correct Answer: GFR increases due to decreased glomerular oncotic pressure

Q15. Which substance is primarily reabsorbed by paracellular solvent drag in proximal tubule?

• Potassium
• ADH
• Urea in the inner medulla only
• Parathyroid hormone

Correct Answer: Potassium

Q16. The concept of filtration fraction is defined as:

• GFR / Renal blood flow (RBF)
• RPF / GFR
• GFR / Renal plasma flow (RPF)
• Urine flow rate / GFR

Correct Answer: GFR / Renal plasma flow (RPF)

Q17. Which receptor activation in the kidney increases renin secretion?

• Beta-1 adrenergic receptors on juxtaglomerular cells
• Alpha-1 adrenergic receptors on afferent arteriole
• V1 vasopressin receptors in collecting duct
• Mineralocorticoid receptors in distal tubule

Correct Answer: Beta-1 adrenergic receptors on juxtaglomerular cells

Q18. Which of the following best describes secretion in the proximal tubule?

• Passive diffusion of proteins from blood to lumen
• Active transport of organic anions and cations into tubular fluid
• Filtration of molecules based solely on size
• Endocytosis of sodium from the lumen

Correct Answer: Active transport of organic anions and cations into tubular fluid

Q19. Which component of Starling forces opposes filtration across the glomerular capillary?

• Glomerular capillary hydrostatic pressure
• Bowman’s space hydrostatic pressure
• Plasma oncotic (colloid osmotic) pressure
• Interstitial oncotic pressure

Correct Answer: Plasma oncotic (colloid osmotic) pressure

Q20. Urea recycling contributes to medullary hyperosmolarity by:

• Active secretion of urea in the proximal tubule
• Reabsorption in the collecting duct and secretion into the thin ascending limb
• Increasing glomerular filtration fraction directly
• Enhancing sodium reabsorption in the distal tubule

Correct Answer: Reabsorption in the collecting duct and secretion into the thin ascending limb

Q21. Which electrolyte is primarily reabsorbed in the proximal tubule by paracellular route driven by solvent drag?

• Sodium
• Glucose
• Calcium
• Water and chloride with accompanying cations like K+

Correct Answer: Water and chloride with accompanying cations like K+

Q22. Loop diuretics can cause metabolic alkalosis primarily because:

• They increase renal bicarbonate reabsorption
• They increase distal sodium delivery leading to enhanced H+ secretion
• They inhibit carbonic anhydrase directly
• They stimulate ADH release

Correct Answer: They increase distal sodium delivery leading to enhanced H+ secretion

Q23. Which transporter in the cortical collecting duct directly mediates potassium secretion?

• ENaC (epithelial sodium channel)
• Na+-K+-ATPase on basolateral membrane and apical K+ channels
• Na+-Cl− cotransporter (NCC)
• Na+-glucose cotransporter (SGLT)

Correct Answer: Na+-K+-ATPase on basolateral membrane and apical K+ channels

Q24. Which renal change is expected with administration of an ACE inhibitor?

• Increased efferent arteriolar constriction
• Decreased angiotensin II leading to decreased efferent arteriolar tone and reduced GFR
• Increased aldosterone secretion
• Enhanced proximal tubule sodium reabsorption

Correct Answer: Decreased angiotensin II leading to decreased efferent arteriolar tone and reduced GFR

Q25. Which statement about renal handling of glucose is correct?

• Glucose is secreted into the tubule by SGLT transporters
• Below the Tm, glucose appears in urine
• Glucose is freely filtered and completely reabsorbed until transport maximum is exceeded
• Glucose clearance exceeds GFR in normal conditions

Correct Answer: Glucose is freely filtered and completely reabsorbed until transport maximum is exceeded

Q26. Which process is most responsible for concentrated urine formation in response to dehydration?

• Decreased ADH secretion
• Increased medullary interstitial osmolarity plus ADH-mediated water reabsorption in collecting duct
• Increased proximal tubular water secretion
• Blocking urea recycling

Correct Answer: Increased medullary interstitial osmolarity plus ADH-mediated water reabsorption in collecting duct

Q27. Clearance of creatinine slightly overestimates GFR because:

• Creatinine is reabsorbed in proximal tubule
• Creatinine is secreted by proximal tubule cells
• Creatinine is metabolized by liver before excretion
• Creatinine is bound to plasma proteins preventing filtration

Correct Answer: Creatinine is secreted by proximal tubule cells

Q28. Which part of nephron is the primary site for bicarbonate reclamation?

• Proximal convoluted tubule
• Thin descending limb
• Distal convoluted tubule
• Collecting duct

Correct Answer: Proximal convoluted tubule

Q29. A drug that blocks ENaC in the collecting duct will most likely cause:

• Hypokalemia
• Hyperkalemia
• Metabolic alkalosis
• Increased aldosterone secretion

Correct Answer: Hyperkalemia

Q30. Parathyroid hormone (PTH) acts on the kidney to:

• Increase phosphate reabsorption in proximal tubule
• Decrease calcium reabsorption in distal tubule
• Decrease phosphate reabsorption and increase calcium reabsorption
• Stimulate ADH release

Correct Answer: Decrease phosphate reabsorption and increase calcium reabsorption

Q31. Which renal mechanism helps conserve bicarbonate during metabolic acidosis?

• Decreased ammonium production
• Enhanced bicarbonate excretion in urine
• Increased ammoniagenesis and H+ secretion
• Reduced reabsorption of filtered bicarbonate

Correct Answer: Increased ammoniagenesis and H+ secretion

Q32. Which of the following increases urea excretion into the renal medulla to aid water reabsorption?

• Aldosterone
• High-protein diet and ADH
• Low ADH levels
• Acetazolamide use

Correct Answer: High-protein diet and ADH

Q33. Which condition would decrease GFR acutely?

• Dilation of afferent arteriole
• Constriction of efferent arteriole
• Severe hypotension leading to decreased renal perfusion
• Administration of low dose angiotensin II

Correct Answer: Severe hypotension leading to decreased renal perfusion

Q34. Which transporter is inhibited by thiazide diuretics in the distal convoluted tubule?

• Na+-K+-2Cl− cotransporter
• Na+-Cl− cotransporter (NCC)
• Epithelial sodium channel (ENaC)
• Na+-glucose cotransporter (SGLT)

Correct Answer: Na+-Cl− cotransporter (NCC)

Q35. Titratable acidity in urine primarily reflects the excretion of H+ buffered by which compound?

• Ammonia
• Bicarbonate
• Phosphate
• Urea

Correct Answer: Phosphate

Q36. Which cell type in the collecting duct is primarily responsible for acid secretion?

• Principal cells secreting potassium
• Interstitial fibroblasts
• Alpha-intercalated cells secreting H+
• Macula densa cells

Correct Answer: Alpha-intercalated cells secreting H+

Q37. Renal excretion of drugs that are weak acids can be enhanced by:

• Acidifying urine
• Alkalinizing urine
• Inhibiting tubular secretion
• Increasing plasma protein binding

Correct Answer: Alkalinizing urine

Q38. The main effect of atrial natriuretic peptide (ANP) on the kidney is to:

• Increase sodium reabsorption in collecting duct
• Constrict afferent arteriole and decrease GFR
• Promote natriuresis by increasing GFR and inhibiting tubular sodium reabsorption
• Stimulate aldosterone secretion

Correct Answer: Promote natriuresis by increasing GFR and inhibiting tubular sodium reabsorption

Q39. Which of the following best describes fractional excretion of sodium (FENa)?

• Urinary sodium concentration divided by plasma sodium concentration
• Fraction of filtered sodium excreted in urine = (Excreted Na)/(Filtered Na)
• GFR multiplied by urine flow rate
• Renal plasma flow multiplied by plasma sodium concentration

Correct Answer: Fraction of filtered sodium excreted in urine = (Excreted Na)/(Filtered Na)

Q40. In the cortical collecting duct, aldosterone increases sodium reabsorption by:

• Directly inserting aquaporins in apical membrane
• Upregulating ENaC and basolateral Na+-K+-ATPase expression
• Blocking ROMK channels
• Increasing prostaglandin synthesis

Correct Answer: Upregulating ENaC and basolateral Na+-K+-ATPase expression

Q41. Which enzyme in the proximal tubule is critical for reclaiming filtered bicarbonate?

• Carbonic anhydrase
• Adenylate cyclase
• Glutaminase
• Renin

Correct Answer: Carbonic anhydrase

Q42. Which statement about the vasa recta is true?

• It actively pumps sodium into the medullary interstitium
• It prevents washout of medullary osmotic gradient by countercurrent exchange
• It is impermeable to water
• It is located primarily around cortical nephrons only

Correct Answer: It prevents washout of medullary osmotic gradient by countercurrent exchange

Q43. Which renal change occurs with NSAID administration that can affect GFR?

• Inhibition of afferent arteriolar vasodilation via reduced prostaglandin synthesis, decreasing GFR
• Increased renin secretion leading to increased GFR
• Enhanced ADH release increasing urine output
• Activation of macula densa to raise GFR

Correct Answer: Inhibition of afferent arteriolar vasodilation via reduced prostaglandin synthesis, decreasing GFR

Q44. The physiologic role of proximal tubular Na+/H+ exchanger (NHE3) includes:

• Secretion of potassium into lumen
• Reabsorption of bicarbonate via H+ secretion
• Primary site of urine concentration
• Regulation of aldosterone release

Correct Answer: Reabsorption of bicarbonate via H+ secretion

Q45. Which solute’s renal handling is characterized by filtration, complete reabsorption via transporters, and appearance in urine only when plasma exceeds a threshold?

• Inulin
• Glucose
• Creatinine
• PAH

Correct Answer: Glucose

Q46. During volume depletion, which change in renal hemodynamics helps maintain GFR?

• Dilation of efferent arteriole by angiotensin II
• Constriction of efferent arteriole via angiotensin II to maintain glomerular pressure
• Inhibition of sympathetic tone to kidneys
• Increased ANP release

Correct Answer: Constriction of efferent arteriole via angiotensin II to maintain glomerular pressure

Q47. Which of the following contributes to potassium wasting when using loop diuretics?

• Decreased distal sodium delivery
• Increased distal sodium delivery enhancing K+ secretion
• Direct stimulation of aldosterone receptors
• Blocking ENaC channels

Correct Answer: Increased distal sodium delivery enhancing K+ secretion

Q48. Which parameter is directly measured to calculate renal plasma flow using PAH clearance?

• Plasma inulin concentration
• Urine flow rate, urine PAH concentration and plasma PAH concentration
• Plasma creatinine only
• GFR and filtration fraction

Correct Answer: Urine flow rate, urine PAH concentration and plasma PAH concentration

Q49. Fanconi syndrome primarily affects which aspect of renal physiology?

• Distal acidification in collecting duct
• Proximal tubular reabsorption leading to generalized proximal tubular dysfunction
• Loop of Henle countercurrent multiplication only
• Glomerular filtration selectivity exclusively

Correct Answer: Proximal tubular reabsorption leading to generalized proximal tubular dysfunction

Q50. Which statement best explains why the thin descending limb is critical for urine concentration?

• It actively transports NaCl out of tubule
• It is highly permeable to water, allowing equilibration with medullary interstitium
• It secretes urea into the lumen via transporters
• It contains ADH receptors that insert aquaporins

Correct Answer: It is highly permeable to water, allowing equilibration with medullary interstitium

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

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