Functions of kidney MCQs With Answer

Understanding the Functions of kidney MCQs With Answer is essential for B.Pharm students preparing for exams in pharmacology, physiology, and therapeutics. This concise guide emphasizes renal physiology, drug elimination, acid–base balance, electrolyte handling, and hormonal roles like erythropoietin and vitamin D activation. Each MCQ targets clinically relevant mechanisms—glomerular filtration, tubular reabsorption/secretion, transporters, renal clearance, diuretic sites, and pathologies—helping you link theory to drug dosing and patient care. Keywords included for SEO: Functions of kidney MCQs With Answer, kidney functions MCQs, renal physiology, B.Pharm kidney questions. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which segment of the nephron is primarily responsible for bulk reabsorption of filtered sodium, water, and glucose?

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

Correct Answer: Proximal convoluted tubule

Q2. The main driving force for glomerular filtration is:

• Bowman’s capsule oncotic pressure
• Glomerular capillary hydrostatic pressure
• Renal interstitial hydrostatic pressure
• Peritubular capillary hydrostatic pressure

Correct Answer: Glomerular capillary hydrostatic pressure

Q3. Clearance of inulin is used clinically to measure which renal parameter?

• Renal plasma flow
• Effective renal plasma flow
• Glomerular filtration rate
• Tubular secretion rate

Correct Answer: Glomerular filtration rate

Q4. Which substance is commonly used to estimate effective renal plasma flow (ERPF) because it is nearly completely cleared by the kidneys?

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

Correct Answer: Para-aminohippuric acid (PAH)

Q5. Renal autoregulation of GFR is maintained primarily by which two mechanisms?

• Sodium-potassium pump and ADH release
• Myogenic response and tubuloglomerular feedback
• RAAS activation and sympathetic tone
• ANP release and prostaglandin synthesis

Correct Answer: Myogenic response and tubuloglomerular feedback

Q6. Which transporter mediates glucose reabsorption in the early proximal tubule?

• Na+/K+ ATPase on apical membrane
• SGLT2 (sodium-glucose cotransporter 2)
• GLUT2 on apical membrane
• NHE3 (sodium-hydrogen exchanger)

Correct Answer: SGLT2 (sodium-glucose cotransporter 2)

Q7. The renal handling term ‘threshold’ most accurately refers to:

• The plasma concentration above which a substance appears in urine
• The maximum tubular reabsorption rate (Tm)
• The GFR at which filtration stops
• The minimum urine osmolality achievable

Correct Answer: The plasma concentration above which a substance appears in urine

Q8. Which part of the nephron is impermeable to water but actively reabsorbs NaCl creating the cortico-medullary osmotic gradient?

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

Correct Answer: Thick ascending limb

Q9. Antidiuretic hormone (ADH) increases water reabsorption by inserting which channel into the collecting duct principal cell apical membrane?

• ENaC (epithelial sodium channel)
• AQP2 (aquaporin-2)
• ROMK channel
• NKCC2 cotransporter

Correct Answer: AQP2 (aquaporin-2)

Q10. Aldosterone primarily increases sodium reabsorption and potassium secretion by upregulating which channel in principal cells?

• Na+/K+ ATPase on apical membrane
• ENaC (epithelial sodium channel)
• ROMK on basolateral membrane
• NKCC1 in the collecting duct

Correct Answer: ENaC (epithelial sodium channel)

Q11. Erythropoietin production by the kidney is stimulated mainly by:

• Hypernatremia
• Tubular hypoxia / decreased renal oxygen delivery
• High GFR
• Increased peritubular capillary oncotic pressure

Correct Answer: Tubular hypoxia / decreased renal oxygen delivery

Q12. The kidney activates vitamin D by converting 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D via which enzyme?

• Renal 1α-hydroxylase
• Hepatic 25-hydroxylase
• CYP3A4 in proximal tubule
• Renal aromatase

Correct Answer: Renal 1α-hydroxylase

Q13. Which diuretic acts on the thick ascending limb by inhibiting the NKCC2 transporter?

• Hydrochlorothiazide
• Spironolactone
• Furosemide
• Acetazolamide

Correct Answer: Furosemide

Q14. Carbonic anhydrase inhibitors cause diuresis by reducing reabsorption of which ions in the proximal tubule?

• Sodium and bicarbonate
• Chloride and potassium
• Calcium and phosphate
• Magnesium and sulfate

Correct Answer: Sodium and bicarbonate

Q15. Renal ammoniagenesis primarily in proximal tubule cells helps the kidney regulate:

• Glucose reabsorption
• Acid–base balance by excreting H+ as NH4+
• Renal blood flow via nitric oxide
• Potassium homeostasis only

Correct Answer: Acid–base balance by excreting H+ as NH4+

Q16. Fractional excretion of sodium (FENa) is useful clinically to distinguish between:

• Prerenal azotemia and intrinsic renal failure
• Glomerulonephritis and nephrotic syndrome
• Acute tubular necrosis and urinary tract infection
• Renal artery stenosis and ureteral obstruction

Correct Answer: Prerenal azotemia and intrinsic renal failure

Q17. Which cell type in the glomerulus is responsible for structural support and modulation of filtration surface area through contraction?

• Podocytes
• Mesangial cells
• Endothelial fenestrated cells
• Parietal epithelial cells of Bowman’s capsule

Correct Answer: Mesangial cells

Q18. Proteinuria exceeding 3.5 g/day with hypoalbuminemia, hyperlipidemia, and edema characterizes which syndrome?

• Nephritic syndrome
• Nephrotic syndrome
• Acute interstitial nephritis
• Renal tubular acidosis type 4

Correct Answer: Nephrotic syndrome

Q19. The countercurrent multiplier mechanism in the loop of Henle primarily concentrates the medullary interstitium by:

• Active water reabsorption in the ascending limb
• Active NaCl reabsorption in the thick ascending limb and water permeability in the descending limb
• Hormonal action of aldosterone in the loop
• Filtration of urea in the descending limb

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

Q20. A decrease in GFR will have which immediate effect on filtered load of a substance freely filtered and not secreted or reabsorbed?

• Filtered load increases
• Filtered load decreases
• Filtered load remains unchanged
• Filtered load becomes zero only if secretion occurs

Correct Answer: Filtered load decreases

Q21. PAH clearance approximates effective renal plasma flow because PAH is:

• Only filtered but not secreted
• Freely filtered and completely reabsorbed
• Freely filtered and then completely secreted from peritubular capillaries
• Bound to plasma proteins and not filtered

Correct Answer: Freely filtered and then completely secreted from peritubular capillaries

Q22. Tubular maximum (Tm) refers to:

• The maximum GFR achievable
• The plasma concentration at which filtration stops
• The maximum rate at which a solute can be reabsorbed by tubules
• The highest urine flow rate per nephron

Correct Answer: The maximum rate at which a solute can be reabsorbed by tubules

Q23. Loop diuretics can cause which electrolyte abnormality by inhibiting NaCl reabsorption in the thick ascending limb?

• Hyperkalemia and metabolic acidosis
• Hypokalemia and metabolic alkalosis
• Hypernatremia only
• Hypercalcemia due to increased reabsorption

Correct Answer: Hypokalemia and metabolic alkalosis

Q24. The primary site of action for thiazide diuretics is:

• Proximal tubule
• Thick ascending limb of loop of Henle
• Distal convoluted tubule (NaCl cotransporter)
• Collecting duct (ENaC)

Correct Answer: Distal convoluted tubule (NaCl cotransporter)

Q25. Which renal pathology commonly presents with hematuria, hypertension, and RBC casts due to glomerular inflammation?

• Nephrotic syndrome
• Nephritic syndrome
• Renal tubular acidosis type 2
• Minimal change disease

Correct Answer: Nephritic syndrome

Q26. The renin–angiotensin–aldosterone system (RAAS) increases blood pressure mainly by:

• Vasodilation and sodium excretion
• Vasoconstriction and increasing sodium and water retention
• Decreasing aldosterone secretion
• Inhibiting sympathetic outflow

Correct Answer: Vasoconstriction and increasing sodium and water retention

Q27. In proximal tubular cells, the basolateral Na+/K+ ATPase contributes to sodium reabsorption by:

• Pumping Na+ into the tubular lumen
• Creating a low intracellular Na+ concentration that drives apical Na+-coupled transport
• Acting as a chloride channel
• Synthesizing ATP for glomerular filtration

Correct Answer: Creating a low intracellular Na+ concentration that drives apical Na+-coupled transport

Q28. Which of the following is a common marker for estimating GFR in clinical practice despite tubular secretion causing slight overestimation?

• Inulin
• Creatinine
• Urea
• Glucose

Correct Answer: Creatinine

Q29. Renal handling of phosphate is regulated by PTH which primarily causes:

• Increased proximal tubular reabsorption of phosphate
• Decreased proximal tubular reabsorption of phosphate (phosphaturia)
• Increased intestinal phosphate excretion
• No effect on phosphate handling

Correct Answer: Decreased proximal tubular reabsorption of phosphate (phosphaturia)

Q30. Which transporter in the thick ascending limb is essential for medullary hypertonicity and is inhibited by loop diuretics?

• ENaC
• SGLT1
• NKCC2 (Na+-K+-2Cl− cotransporter)
• AE1 (anion exchanger in intercalated cells)

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

Q31. The primary function of alpha-intercalated cells in the collecting duct is:

• Secretion of K+ into the lumen
• Secretion of H+ and reclamation of bicarbonate to maintain acid–base balance
• Reabsorption of glucose
• Synthesis of erythropoietin

Correct Answer: Secretion of H+ and reclamation of bicarbonate to maintain acid–base balance

Q32. Which condition is characterized by defective Na+ reabsorption in the proximal tubule leading to generalized loss of amino acids, glucose, bicarbonate, and phosphate?

• Fanconi syndrome
• Bartter syndrome
• Liddle syndrome
• Gitelman syndrome

Correct Answer: Fanconi syndrome

Q33. Loop diuretics increase urinary calcium excretion by:

• Enhancing paracellular calcium reabsorption in the TAL
• Decreasing lumen-positive potential in the thick ascending limb thus reducing paracellular Ca2+ reabsorption
• Directly blocking PTH receptors
• Upregulating TRPV5 channels in the distal tubule

Correct Answer: Decreasing lumen-positive potential in the thick ascending limb thus reducing paracellular Ca2+ reabsorption

Q34. Which transporter defect causes Liddle syndrome, presenting with hypertension, hypokalemia, and low aldosterone levels?

• Gain-of-function mutation in ENaC causing increased sodium reabsorption
• Defect in NKCC2 producing salt wasting
• Loss of function in Na+/K+ ATPase
• Excessive ROMK activity leading to hyperkalemia

Correct Answer: Gain-of-function mutation in ENaC causing increased sodium reabsorption

Q35. The principal mechanism by which the kidney regulates acid–base balance in metabolic acidosis is:

• Increased urinary bicarbonate excretion only
• Increased ammonia (NH3/NH4+) generation and H+ secretion with new bicarbonate synthesis
• Decreased reabsorption of filtered bicarbonate only
• Excretion of ketone bodies without ammoniagenesis

Correct Answer: Increased ammonia (NH3/NH4+) generation and H+ secretion with new bicarbonate synthesis

Q36. Which renal lab finding suggests prerenal azotemia rather than intrinsic renal damage?

• FENa > 2% and muddy brown casts
• FENa < 1% and concentrated urine with high specific gravity
• Heavy proteinuria and hypoalbuminemia
• Elevated urinary β2-microglobulin indicating tubular injury

Correct Answer: FENa < 1% and concentrated urine with high specific gravity

Q37. Acid retention with normal anion gap metabolic acidosis and hyperkalemia due to hypoaldosteronism is characteristic of which renal tubular acidosis (RTA) type?

• RTA type 1 (distal)
• RTA type 2 (proximal)
• RTA type 4 (hypoaldosteronism)
• RTA due to carbonic anhydrase excess

Correct Answer: RTA type 4 (hypoaldosteronism)

Q38. Which hormone produced by the heart opposes RAAS and increases sodium excretion by promoting renal vasodilation and inhibiting sodium reabsorption?

• Vasopressin (ADH)
• Atrial natriuretic peptide (ANP)
• Angiotensin II
• Renin

Correct Answer: Atrial natriuretic peptide (ANP)

Q39. The main clinical utility of creatinine clearance is to:

• Measure tubular secretion capacity
• Estimate glomerular filtration rate for drug dosing
• Quantify renal ammoniagenesis
• Assess interdialytic weight gain

Correct Answer: Estimate glomerular filtration rate for drug dosing

Q40. Which electrolyte disturbance commonly occurs with chronic loop diuretic therapy and may require monitoring in B.Pharm practice?

• Hyperkalemia without acid–base changes
• Hypokalemia and metabolic alkalosis
• Hypermagnesemia only
• Hyponatremia with hypercalcemia

Correct Answer: Hypokalemia and metabolic alkalosis

Q41. Urea recycling contributes to medullary osmolarity by:

• Being actively reabsorbed in the proximal tubule to increase medullary tonicity
• Being reabsorbed in the collecting duct and secreted into the thin loop, enhancing inner medullary osmolarity
• Being excreted unchanged with no role in concentration
• Inhibiting NKCC2 transport in the thick ascending limb

Correct Answer: Being reabsorbed in the collecting duct and secreted into the thin loop, enhancing inner medullary osmolarity

Q42. Drug dosing in renal impairment often uses which parameter to adjust doses safely?

• Serum potassium concentration
• Estimated GFR or creatinine clearance
• Urine specific gravity
• Plasma albumin only

Correct Answer: Estimated GFR or creatinine clearance

Q43. Which nephron transporter defect is classically associated with Bartter syndrome, presenting with hypokalemia and metabolic alkalosis mimicking chronic loop diuretic use?

• NKCC2 or ROMK defects in the thick ascending limb
• ENaC gain-of-function in collecting duct
• SGLT2 defect in proximal tubule
• Distal H+/K+ ATPase loss in intercalated cells

Correct Answer: NKCC2 or ROMK defects in the thick ascending limb

Q44. Which of the following increases potassium secretion in the collecting duct?

• Low distal flow and low aldosterone
• High distal sodium delivery and aldosterone stimulation
• Low dietary potassium intake only
• Activation of carbonic anhydrase in intercalated cells

Correct Answer: High distal sodium delivery and aldosterone stimulation

Q45. Hypoalbuminemia in nephrotic syndrome leads to which secondary renal-related complication?

• Polyuria due to increased filtration fraction
• Edema due to decreased plasma oncotic pressure
• Metabolic acidosis due to loss of bicarbonate in urine
• Hypernatremia from increased sodium retention only

Correct Answer: Edema due to decreased plasma oncotic pressure

Q46. The filtration barrier of the glomerulus is composed of which three layers?

• Endothelial fenestrations, glomerular basement membrane, podocyte slit diaphragm
• Proximal tubule epithelium, loop of Henle, collecting duct
• Bowman’s capsule parietal layer, mesangium, peritubular capillaries
• Ureteric epithelium, transitional epithelium, detrusor muscle

Correct Answer: Endothelial fenestrations, glomerular basement membrane, podocyte slit diaphragm

Q47. Which laboratory change indicates impaired concentrating ability of the kidney (e.g., diabetes insipidus)?

• High urine osmolality > 800 mOsm/kg
• Low urine osmolality and high plasma sodium
• Low plasma creatinine with concentrated urine
• Increased urine specific gravity with normal plasma sodium

Correct Answer: Low urine osmolality and high plasma sodium

Q48. In patients with chronic kidney disease, decreased 1,25-(OH)2 vitamin D production contributes to:

• Hypercalcemia and suppressed PTH
• Hypocalcemia and secondary hyperparathyroidism
• Increased intestinal phosphate absorption lowering serum phosphate
• Improved bone mineralization

Correct Answer: Hypocalcemia and secondary hyperparathyroidism

Q49. The primary mechanism by which the proximal tubule reabsorbs bicarbonate involves which enzyme?

• Na+/K+ ATPase only
• Carbonic anhydrase facilitating H2O and CO2 handling
• NHE1 acting as a bicarbonate transporter
• Adenylate cyclase increasing cAMP

Correct Answer: Carbonic anhydrase facilitating H2O and CO2 handling

Q50. Hemodialysis replaces which primary kidney functions in end-stage renal disease?

• Endocrine production of erythropoietin and vitamin D activation only
• Filtration/excretion of small solutes and fluid removal but not endocrine functions
• All kidney functions including hormone synthesis completely
• Only acid–base regulation without solute removal

Correct Answer: Filtration/excretion of small solutes and fluid removal but not endocrine functions

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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