Urine formation MCQs With Answer

Introduction:
Understanding urine formation is essential for B.Pharm students studying renal physiology, pharmacokinetics, and drug elimination. This concise guide on “Urine formation MCQs With Answer” covers core concepts such as glomerular filtration, tubular reabsorption, tubular secretion, countercurrent multiplication, concentrating mechanisms, and hormonal regulation by ADH and aldosterone. These focused MCQs emphasize nephron segment functions, transporters, clearance calculations, pathophysiology, and drug interactions affecting renal handling. Practicing these questions will strengthen your clinical reasoning, exam readiness, and ability to predict drug behavior in renal impairment. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which process primarily initiates urine formation?

• Glomerular filtration
• Tubular reabsorption
• Tubular secretion
• Countercurrent multiplication

Correct Answer: Glomerular filtration

Q2. Which three layers make up the glomerular filtration barrier?

• Fenestrated endothelium, basement membrane, podocyte slit diaphragms
• Endothelium, mesangium, collecting duct epithelium
• Proximal tubule brush border, basement membrane, vasa recta
• Podocytes, loop of Henle, distal tubule

Correct Answer: Fenestrated endothelium, basement membrane, podocyte slit diaphragms

Q3. Which force favors filtration across glomerular capillaries?

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

Correct Answer: Glomerular capillary hydrostatic pressure

Q4. Which term describes the volume of plasma completely cleared of a substance per unit time?

• Renal tubular maximum (Tm)
• Filtered load
• Renal clearance
• Glomerular filtration rate

Correct Answer: Renal clearance

Q5. Inulin clearance is used to measure which parameter?

• Effective renal plasma flow (ERPF)
• Glomerular filtration rate (GFR)
• Tubular secretion rate
• Renal threshold

Correct Answer: Glomerular filtration rate (GFR)

Q6. Para-aminohippuric acid (PAH) clearance estimates which renal variable?

• GFR
• ERPF (effective renal plasma flow)
• Renal vascular resistance
• Tubular reabsorption efficiency

Correct Answer: ERPF (effective renal plasma flow)

Q7. Which nephron segment is the primary site for reabsorption of glucose?

• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule
• Collecting duct

Correct Answer: Proximal convoluted tubule

Q8. Which transporter is responsible for glucose reabsorption in the early proximal tubule?

• SGLT2 (sodium-glucose cotransporter 2)
• SGLT1 (sodium-glucose cotransporter 1)
• GLUT2 facilitated diffusion only
• Na+/K+ ATPase directly transports glucose

Correct Answer: SGLT2 (sodium-glucose cotransporter 2)

Q9. When plasma glucose exceeds the renal threshold, what happens to urinary glucose?

• It is fully reabsorbed
• It appears in urine (glycosuria)
• It is secreted actively into tubule
• It is metabolized in the collecting duct

Correct Answer: It appears in urine (glycosuria)

Q10. Which segment creates the medullary osmotic gradient essential for urine concentration?

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

Correct Answer: Loop of Henle

Q11. Countercurrent multiplication depends mainly on which property of the loop of Henle?

• Active NaCl transport in thick ascending limb and water permeability in descending limb
• High water permeability in ascending limb
• Urea secretion in the thin ascending limb only
• Active bicarbonate secretion in the descending limb

Correct Answer: Active NaCl transport in thick ascending limb and water permeability in descending limb

Q12. ADH (vasopressin) increases water reabsorption by inserting which channels into collecting duct cells?

• ENaC channels
• Aquaporin-2 channels
• Glucose transporters
• Cl− channels

Correct Answer: Aquaporin-2 channels

Q13. Aldosterone primarily increases reabsorption of which ion in the distal nephron?

• Calcium
• Sodium
• Potassium
• Bicarbonate

Correct Answer: Sodium

Q14. Which diuretic acts on the thick ascending limb by inhibiting the Na-K-2Cl cotransporter?

• Thiazide diuretics
• Loop diuretics (e.g., furosemide)
• Carbonic anhydrase inhibitors
• Potassium-sparing diuretics

Correct Answer: Loop diuretics (e.g., furosemide)

Q15. Thiazide diuretics inhibit which transporter in the distal convoluted tubule?

• Na-Cl cotransporter (NCC)
• Na-K-2Cl cotransporter
• SGLT2
• ENaC channel

Correct Answer: Na-Cl cotransporter (NCC)

Q16. Which substance is secreted by proximal tubule organic anion transporters and can be used to study tubular secretion of drugs?

• Inulin
• PAH (para-aminohippuric acid)
• Glucose
• Urea

Correct Answer: PAH (para-aminohippuric acid)

Q17. Renal handling: If the clearance of a substance is greater than GFR, this indicates what?

• Net reabsorption
• Filterability only
• Net secretion into the tubule
• No renal handling

Correct Answer: Net secretion into the tubule

Q18. Tubular maximum (Tm) refers to:

• The maximum GFR attainable
• The maximal transport rate of a substance by tubules
• The volume of urine produced per minute
• The highest plasma concentration without filtration

Correct Answer: The maximal transport rate of a substance by tubules

Q19. Which condition increases BUN-to-creatinine ratio suggesting prerenal azotemia?

• Intrinsic renal failure with low BUN
• Dehydration causing increased reabsorption of urea
• Acute tubular necrosis lowering BUN
• Postrenal obstruction lowering creatinine

Correct Answer: Dehydration causing increased reabsorption of urea

Q20. Which part of nephron is impermeable to water but actively reabsorbs NaCl?

• Proximal tubule
• Thin descending limb
• Thick ascending limb
• Collecting duct

Correct Answer: Thick ascending limb

Q21. Urea recycling contributes to medullary osmolarity. Which transporter or process is most involved?

• Urea transporters (UT-A) in inner medullary collecting duct
• Na+/K+ ATPase in proximal tubule only
• Glomerular filtration of urea exclusively
• Active secretion of urea in thick ascending limb

Correct Answer: Urea transporters (UT-A) in inner medullary collecting duct

Q22. What is the effect of sympathetic stimulation on GFR during severe hemorrhage?

• Increases GFR by dilating afferent arteriole
• Decreases GFR by constricting afferent arteriole
• No effect on renal blood flow
• Increases filtration fraction without changing GFR

Correct Answer: Decreases GFR by constricting afferent arteriole

Q23. Which hormone increases Na+ reabsorption and K+ secretion in principal cells?

• ADH
• Aldosterone
• ANP (atrial natriuretic peptide)
• PTH (parathyroid hormone)

Correct Answer: Aldosterone

Q24. A substance freely filtered, not reabsorbed or secreted, has clearance equal to:

• Zero
• Inulin clearance (GFR)
• PAH clearance (ERPF)
• Renal plasma flow plus GFR

Correct Answer: Inulin clearance (GFR)

Q25. Which electrolyte’s handling is most affected by loop diuretics leading to hypokalemia?

• Calcium retention
• Potassium wasting due to increased distal delivery of Na+
• Increased phosphate reabsorption
• Hypermagnesemia

Correct Answer: Potassium wasting due to increased distal delivery of Na+

Q26. Carbonic anhydrase inhibitors cause diuresis mainly by blocking reabsorption of which ion?

• Chloride
• Bicarbonate
• Sodium via ENaC
• Urea

Correct Answer: Bicarbonate

Q27. Which renal parameter is directly measured by inulin clearance but is often estimated clinically by creatinine clearance?

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

Correct Answer: Glomerular filtration rate (GFR)

Q28. Which segment is the major site of bicarbonate reclamation in the nephron?

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

Correct Answer: Proximal tubule

Q29. A defect in Na+/K+ ATPase in tubular cells would most directly impair:

• Glomerular filtration
• Secondary active transport across apical membrane
• Passive diffusion of urea
• ADH binding to receptors

Correct Answer: Secondary active transport across apical membrane

Q30. Renal clearance of creatinine slightly overestimates GFR because:

• Creatinine is secreted by proximal tubule
• Creatinine is reabsorbed in distal tubule
• Creatinine is metabolized in kidney
• Plasma creatinine is filtered incompletely

Correct Answer: Creatinine is secreted by proximal tubule

Q31. Which transporter in proximal tubule handles organic anions and is important for secretion of many drugs?

• OAT (organic anion transporter)
• OCT (organic cation transporter)
• PEPT (peptide transporter)
• SGLT (sodium-glucose transporter)

Correct Answer: OAT (organic anion transporter)

Q32. Which change would increase urinary concentration during dehydration?

• Decreased ADH secretion
• Increased urine flow rate
• Increased medullary interstitial osmolarity
• Inhibition of urea recycling

Correct Answer: Increased medullary interstitial osmolarity

Q33. Bartter syndrome mimics the action of which diuretic pharmacologically?

• Thiazides
• Loop diuretics
• Potassium-sparing diuretics
• Carbonic anhydrase inhibitors

Correct Answer: Loop diuretics

Q34. The renal handling of ammonium (NH4+) is important for:

• Glucose homeostasis
• Acid-base balance and excretion of acid
• Regulation of blood pressure through renin
• Secretion of aldosterone

Correct Answer: Acid-base balance and excretion of acid

Q35. Which clinical test assesses concentrating ability of kidney by measuring urine osmolality after water deprivation?

• Creatinine clearance test
• Water deprivation test
• PRA (plasma renin activity)
• 24-hour urine protein

Correct Answer: Water deprivation test

Q36. A patient with SIADH (syndrome of inappropriate ADH) typically presents with:

• Polyuria and hypernatremia
• Hyponatremia and concentrated urine
• Hyperkalemia and dilute urine
• High aldosterone and metabolic alkalosis

Correct Answer: Hyponatremia and concentrated urine

Q37. Which stone-forming substance is increased in urine by loop diuretics and decreased by thiazides?

• Uric acid
• Calcium
• Magnesium
• Oxalate

Correct Answer: Calcium

Q38. Which renal clearance pattern indicates a substance is completely reabsorbed? (Csubstance = ?)

• Greater than GFR
• Equal to renal plasma flow
• Less than GFR, approaching zero
• Equal to GFR

Correct Answer: Less than GFR, approaching zero

Q39. In metabolic acidosis, the kidney increases acid excretion mainly by:

• Increasing HCO3− secretion into urine
• Decreasing ammoniagenesis
• Increasing H+ secretion and ammonium excretion
• Blocking H+ secretion in proximal tubule

Correct Answer: Increasing H+ secretion and ammonium excretion

Q40. Which ion transport in collecting duct principal cells creates lumen-negative potential favoring K+ secretion?

• Basolateral Cl− uptake
• Apical Na+ reabsorption via ENaC
• Apical H+ secretion
• Urea diffusion

Correct Answer: Apical Na+ reabsorption via ENaC

Q41. Which condition causes non-oliguric polyuria with low urine osmolarity due to ADH resistance?

• Central diabetes insipidus
• Nephrogenic diabetes insipidus
• Syndrome of inappropriate ADH
• Acute tubular necrosis

Correct Answer: Nephrogenic diabetes insipidus

Q42. The filtration fraction is defined as:

• GFR divided by RBF (renal blood flow)
• RPF divided by GFR
• GFR divided by RPF (renal plasma flow)
• Total urine flow divided by plasma volume

Correct Answer: GFR divided by RPF (renal plasma flow)

Q43. Which drug class can inhibit aldosterone’s effect at the collecting duct leading to potassium retention?

• Loop diuretics
• Thiazide diuretics
• Aldosterone receptor antagonists (e.g., spironolactone)
• Carbonic anhydrase inhibitors

Correct Answer: Aldosterone receptor antagonists (e.g., spironolactone)

Q44. Which measurement best reflects osmotic excretion of solutes in urine?

• Urine specific gravity only
• Urine osmolality
• Plasma sodium concentration
• Urine pH

Correct Answer: Urine osmolality

Q45. In proximal tubular reabsorption, solvent drag contributes to reabsorption of:

• Sodium only
• Water and accompanying solutes like chloride and urea
• Large proteins intact
• Only organic ions

Correct Answer: Water and accompanying solutes like chloride and urea

Q46. Which renal adaptation occurs in chronic kidney disease affecting urine formation?

• Increased GFR in each nephron (hyperfiltration) while total GFR falls
• Increased total nephron number
• Improved concentrating ability
• Enhanced drug clearance uniformly

Correct Answer: Increased GFR in each nephron (hyperfiltration) while total GFR falls

Q47. Which transporter in proximal tubule is involved in bicarbonate reclamation by forming H+ for luminal reaction with filtered HCO3−?

• Na+/H+ exchanger (NHE3)
• SGLT2
• Na+/K+/2Cl− cotransporter
• ENaC

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

Q48. Methicillin and some beta-lactam antibiotics compete for which renal process, potentially altering drug levels?

• Glomerular filtration of proteins
• Proximal tubular secretion via organic anion transporters
• Loop diuretic binding sites
• ADH receptor activation

Correct Answer: Proximal tubular secretion via organic anion transporters

Q49. Urine pH is most important in determining renal excretion of which compound class?

• Proteins
• Weak acids and weak bases (ionization-dependent excretion)
• Inorganic salts only
• Glucose and amino acids

Correct Answer: Weak acids and weak bases (ionization-dependent excretion)

Q50. Which physiologic change increases filtration fraction transiently?

• Dilation of efferent arteriole only
• Constriction of efferent arteriole increasing glomerular hydrostatic pressure
• Decrease in plasma oncotic pressure without GFR change
• Increased renal blood flow with equal change in GFR

Correct Answer: Constriction of efferent arteriole increasing glomerular hydrostatic pressure

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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