Renal Fucntions

*Question: What percentage of cardiac output do the kidneys receive per minute?
A) 10%
B) 25%
C) 50%
D) 75%

*Answer: B) 25%

*Question: Which kidney is located slightly lower and why?
A) Left kidney; to accommodate the spleen
B) Right kidney; to make room for the liver
C) Left kidney; to make room for the stomach
D) Right kidney; to accommodate the pancreas

*Answer: B) Right kidney; to make room for the liver

*Question: How many functional units (nephrons) does each kidney contain?
A) 500,000 to 750,000
B) 750,000 to 1 million
C) 1 to 1.5 million
D) 2 to 3 million

*Answer: C) 1 to 1.5 million

*Question: Which hormone is responsible for triggering erythrocyte production?
A) Renin
B) Aldosterone
C) Erythropoietin
D) Calcitriol

*Answer: C) Erythropoietin

*Question: What is the active form of vitamin D produced by the kidneys?
A) Cholecalciferol
B) Ergocalciferol
C) 25-hydroxyvitamin D
D) 1,25-dihydroxycholecalciferol (calcitriol)

*Answer: D) 1,25-dihydroxycholecalciferol (calcitriol)

*Question: What percentage of nephrons are cortical nephrons?
A) 65%
B) 75%
C) 85%
D) 95%

*Answer: C) 85%

*Question: Which type of nephron is essential for the countercurrent mechanism?
A) Cortical nephrons
B) Juxtamedullary nephrons
C) Afferent nephrons
D) Peritubular nephrons

*Answer: B) Juxtamedullary nephrons

*Question: Which arteriole carries blood INTO the glomerulus?
A) Efferent arteriole
B) Peritubular arteriole
C) Afferent arteriole
D) Renal arteriole

*Answer: C) Afferent arteriole

*Question: What structure surrounds the glomerulus and collects filtrate?
A) Proximal convoluted tubule
B) Bowman's capsule
C) Distal convoluted tubule
D) Collecting duct

*Answer: B) Bowman's capsule

*Question: Where does the majority of reabsorption occur in the nephron?
A) Distal convoluted tubule
B) Loop of Henle
C) Proximal convoluted tubule
D) Collecting duct

*Answer: C) Proximal convoluted tubule

*Question: Which loop of Henle is water permeable but impermeable to solutes?
A) Ascending loop
B) Descending loop
C) Both loops equally
D) Neither loop

*Answer: B) Descending loop

*Question: Which loop of Henle is water impermeable but permeable to solutes?
A) Ascending loop
B) Descending loop
C) Both loops equally
D) Neither loop

*Answer: A) Ascending loop

*Question: What is the primary function of the distal convoluted tubule in pH balance?
A) Secreting bicarbonate and reabsorbing hydrogen ions
B) Reabsorbing bicarbonate and secreting hydrogen ions
C) Secreting both bicarbonate and hydrogen ions
D) Reabsorbing both bicarbonate and hydrogen ions

*Answer: B) Reabsorbing bicarbonate and secreting hydrogen ions

*Question: The concentration of urine in the collecting duct is dependent on which hormone?
A) Aldosterone
B) Renin
C) ADH (antidiuretic hormone)
D) Angiotensin II

*Answer: C) ADH (antidiuretic hormone)

*Question: Which structure detects changes in blood pressure and sodium chloride levels?
A) Macula densa
B) Juxtaglomerular apparatus
C) Peritubular capillaries
D) Vasa recta

*Answer: B) Juxtaglomerular apparatus

*Question: What is the approximate renal blood flow per minute?
A) 600 mL/min
B) 900 mL/min
C) 1200 mL/min
D) 1500 mL/min

*Answer: C) 1200 mL/min

*Question: What is the approximate plasma flow through the kidneys per minute?
A) 400-500 mL/min
B) 600-700 mL/min
C) 800-900 mL/min
D) 1000-1100 mL/min

*Answer: B) 600-700 mL/min

*Question: What molecular weight threshold does the glomerulus use for nonselective filtration?
A) Less than 50,000 kDa
B) Less than 60,000 kDa
C) Less than 70,000 kDa
D) Less than 80,000 kDa

*Answer: C) Less than 70,000 kDa

*Question: What is the approximate glomerular filtration rate (GFR)?
A) 80-100 mL/min
B) 100-110 mL/min
C) 120-125 mL/min
D) 140-160 mL/min

*Answer: C) 120-125 mL/min

*Question: What is the specific gravity of the initial ultrafiltrate produced by the glomerulus?
A) 1.000
B) 1.005
C) 1.010
D) 1.020

*Answer: C) 1.010

*Question: What prevents proteins from passing through the glomerular filtration barrier despite being small enough?
A) Large molecular size
B) Shield of negativity
C) High oncotic pressure
D) Podocyte tight junctions

*Answer: B) Shield of negativity

*Question: Which cellular layer of the glomerular filtration barrier contains pores?
A) Basement membrane
B) Podocytes
C) Fenestrated endothelium
D) Mesangial cells

*Answer: C) Fenestrated endothelium

*Question: What is the glomerular hydrostatic pressure?
A) 32 mmHg
B) 45 mmHg
C) 60 mmHg
D) 75 mmHg

*Answer: C) 60 mmHg

*Question: What is the Bowman's capsule hydrostatic pressure?
A) 0 mmHg
B) 18 mmHg
C) 32 mmHg
D) 60 mmHg

*Answer: B) 18 mmHg

*Question: What is the glomerular capillary colloid osmotic pressure?
A) 18 mmHg
B) 24 mmHg
C) 32 mmHg
D) 40 mmHg

*Answer: C) 32 mmHg

*Question: What is the net filtration pressure in the glomerulus?
A) 5 mmHg
B) 10 mmHg
C) 15 mmHg
D) 20 mmHg

*Answer: B) 10 mmHg

*Question: Why is Bowman's capsule colloid osmotic pressure 0 mmHg?
A) High hydrostatic pressure prevents osmosis
B) No protein is present in the filtrate to pull water
C) The capsule walls are impermeable
D) Active transport neutralizes the pressure

*Answer: B) No protein is present in the filtrate to pull water

*Question: Which cells secrete renin in the juxtaglomerular apparatus?
A) Macula densa cells
B) Mesangial cells
C) Juxtaglomerular cells
D) Podocytes

*Answer: C) Juxtaglomerular cells

*Question: Where is the macula densa located?
A) Afferent arteriole
B) Proximal convoluted tubule
C) Distal convoluted tubule
D) Collecting duct

*Answer: C) Distal convoluted tubule

*Question: What does the macula densa sense?
A) Blood pressure
B) Glucose levels
C) Sodium content
D) pH changes

*Answer: C) Sodium content

*Question: What enzyme converts angiotensinogen to angiotensin I?
A) ACE
B) Renin
C) Aldosterone
D) Angiotensinase

*Answer: B) Renin

*Question: Where is angiotensin-converting enzyme (ACE) primarily located?
A) Kidneys
B) Liver
C) Lungs
D) Heart

*Answer: C) Lungs

*Question: When blood pressure increases, what happens to the afferent arteriole?
A) Dilates
B) Constricts
C) No change
D) Collapses

*Answer: B) Constricts

*Question: When blood pressure decreases, what happens to the afferent arteriole?
A) Dilates
B) Constricts
C) No change
D) Collapses

*Answer: A) Dilates

*Question: What percentage of filtered water is reabsorbed by the tubules?
A) 85%
B) 90%
C) 95%
D) 99%

*Answer: D) 99%

*Question: What type of transport requires a carrier protein and ATP?
A) Passive transport
B) Active transport
C) Facilitated diffusion
D) Simple diffusion

*Answer: B) Active transport

*Question: What is the renal threshold for glucose?
A) 100-120 mg/dL
B) 120-140 mg/dL
C) 160-180 mg/dL
D) 200-220 mg/dL

*Answer: C) 160-180 mg/dL

*Question: What percentage of filtered urea is reabsorbed?
A) 0%
B) 25%
C) 50%
D) 100%

*Answer: C) 50%

*Question: What percentage of filtered glucose is reabsorbed in healthy individuals?
A) 75%
B) 85%
C) 95%
D) 100%

*Answer: D) 100%

*Question: What percentage of filtered creatinine is reabsorbed?
A) 0%
B) 25%
C) 50%
D) 75%

*Answer: A) 0%

*Question: What is renal glycosuria?
A) Glucose in urine due to diabetes mellitus
B) Glucose in urine with normal blood glucose due to tubular damage
C) Absence of glucose in urine despite high blood glucose
D) Glucose in urine due to dehydration

*Answer: B) Glucose in urine with normal blood glucose due to tubular damage

*Question: Which transporter is responsible for glucose entry into proximal tubule cells?
A) GLUT
B) SGLT
C) ENaC
D) NKCC2

*Answer: B) SGLT

*Question: Which transporter allows glucose to exit proximal tubule cells?
A) GLUT (facilitated diffusion)
B) SGLT
C) ENaC
D) NKCC2

*Answer: A) GLUT (facilitated diffusion)

*Question: How are small-weight proteins reabsorbed in the proximal tubule?
A) Active transport
B) Passive diffusion
C) Pinocytosis
D) Facilitated diffusion

*Answer: C) Pinocytosis

*Question: Which aquaporin is abundant in the proximal convoluted tubule?
A) Aquaporin-1
B) Aquaporin-2
C) Aquaporin-3
D) Aquaporin-4

*Answer: A) Aquaporin-1

*Question: Which aquaporin in the collecting duct requires ADH to open?
A) Aquaporin-1
B) Aquaporin-2
C) Aquaporin-3
D) Aquaporin-4

*Answer: B) Aquaporin-2

*Question: What is the NKCC2 co-transporter responsible for?
A) Glucose and sodium reabsorption in PCT
B) Sodium, potassium, and chloride reabsorption in thick ALOH
C) Sodium and chloride reabsorption in DCT
D) Sodium reabsorption in collecting duct

*Answer: B) Sodium, potassium, and chloride reabsorption in thick ALOH

*Question: Which class of diuretics inhibits NKCC2?
A) Thiazide diuretics
B) Loop diuretics
C) Potassium-sparing diuretics
D) Osmotic diuretics

*Answer: B) Loop diuretics

*Question: Where do thiazide diuretics primarily work?
A) Proximal convoluted tubule
B) Thick ascending loop of Henle
C) Early distal convoluted tubule
D) Collecting duct

*Answer: C) Early distal convoluted tubule

*Question: Which channel is blocked by potassium-sparing diuretics like amiloride?
A) NKCC2
B) Sodium-chloride co-transporter
C) ENaC (epithelial sodium channel)
D) ROMK channel

*Answer: C) ENaC (epithelial sodium channel)

*Question: What maintains the high osmotic gradient in the renal medulla?
A) Active sodium reabsorption in PCT
B) Countercurrent mechanism
C) ADH secretion
D) Aldosterone action

*Answer: B) Countercurrent mechanism

*Question: What happens to urine volume when ADH is decreased?
A) Urine volume decreases (concentrated)
B) Urine volume increases (dilute)
C) No change in urine volume
D) Urine becomes more acidic

*Answer: B) Urine volume increases (dilute)

*Question: What happens to urine volume when ADH is increased?
A) Urine volume decreases (concentrated)
B) Urine volume increases (dilute)
C) No change in urine volume
D) Urine becomes more alkaline

*Answer: A) Urine volume decreases (concentrated)

*Question: What is the major site for removal of protein-bound substances that cannot be filtered?
A) Glomerulus
B) Proximal convoluted tubule
C) Loop of Henle
D) Collecting duct

*Answer: B) Proximal convoluted tubule

*Question: What is the normal blood pH?
A) 7.0
B) 7.2
C) 7.4
D) 7.6

*Answer: C) 7.4

*Question: What is the primary buffer in the blood?
A) Phosphate
B) Bicarbonate
C) Ammonia
D) Protein

*Answer: B) Bicarbonate

*Question: What percentage of filtered bicarbonate is reabsorbed?
A) 50%
B) 75%
C) 90%
D) Almost 100%

*Answer: D) Almost 100%

*Question: What is renal tubular acidosis?
A) Inability to produce alkaline urine
B) Inability to produce acidic urine in the presence of metabolic acidosis
C) Excessive acid production by kidneys
D) Inability to reabsorb bicarbonate

*Answer: B) Inability to produce acidic urine in the presence of metabolic acidosis

*Question: Where is ammonia primarily produced in the nephron?
A) Glomerulus
B) Proximal convoluted tubule from glutamine
C) Loop of Henle
D) Collecting duct

*Answer: B) Proximal convoluted tubule from glutamine

*Question: What is the gold standard for evaluating glomerular filtration?
A) Blood urea nitrogen
B) Serum creatinine
C) Clearance tests
D) Urinalysis

*Answer: C) Clearance tests

*Question: What type of urine specimen is required for clearance tests?
A) Random urine
B) First morning void
C) 24-hour urine
D) Clean-catch midstream

*Answer: C) 24-hour urine

*Question: What was the earliest glomerular filtration test?
A) Creatinine clearance
B) Urea clearance
C) Inulin clearance
D) Cystatin C

*Answer: B) Urea clearance

*Question: What is the main disadvantage of urea clearance?
A) Exogenous substance required
B) 50% of filtered urea is reabsorbed by tubules
C) Causes anaphylactic shock
D) Too expensive

*Answer: B) 50% of filtered urea is reabsorbed by tubules

*Question: What urine flow rate must be maintained for accurate urea clearance?
A) 1 mL/min
B) 2 mL/min
C) 5 mL/min
D) 10 mL/min

*Answer: B) 2 mL/min

*Question: What is the gold standard substance for measuring GFR?
A) Creatinine
B) Urea
C) Inulin
D) Cystatin C

*Answer: C) Inulin

*Question: What is inulin?
A) A protein marker
B) A polymer of fructose
C) A nucleotide
D) An amino acid

*Answer: B) A polymer of fructose

*Question: What is the main disadvantage of inulin clearance?
A) It is reabsorbed by tubules
B) It is secreted by tubules
C) It is exogenous and requires infusion
D) It is unstable

*Answer: C) It is exogenous and requires infusion

*Question: What is an advantage of using radionuclides for GFR testing?
A) No urine specimen needed
B) Less expensive than other methods
C) Can be performed at home
D) More accurate than inulin

*Answer: A) No urine specimen needed

*Question: What are examples of radionuclides used for GFR testing?
A) Inulin and PAH
B) 125I-iothalamate and 99mTc-DTPA
C) Creatinine and urea
D) Cystatin C and beta-2-microglobulin

*Answer: B) 125I-iothalamate and 99mTc-DTPA

*Question: What forms part of the class I MHC present in leukocytes?
A) Cystatin C
B) Beta-2-microglobulin
C) Creatinine
D) Inulin

*Answer: B) Beta-2-microglobulin

*Question: When is beta-2-microglobulin concentration increased in urine?
A) When glomerular filtration increases
B) When tubular reabsorption is reduced (tubular damage)
C) When tubular secretion increases
D) When ADH levels are high

*Answer: B) When tubular reabsorption is reduced (tubular damage)

*Question: What is a disadvantage of beta-2-microglobulin testing?
A) It is exogenous
B) It degrades in acidic environments
C) It requires 48-hour urine collection
D) It is too expensive

*Answer: B) It degrades in acidic environments

*Question: What produces cystatin C?
A) Only kidney cells
B) Only liver cells
C) All nucleated cells
D) Only blood cells

*Answer: C) All nucleated cells

*Question: How is cystatin C related to GFR?
A) Directly proportional
B) Inversely proportional
C) No relationship
D) Exponentially proportional

*Answer: B) Inversely proportional

*Question: What is an advantage of cystatin C for GFR testing?
A) It requires 24-hour urine
B) No urine sample is needed
C) It is the least expensive test
D) It measures tubular function

*Answer: B) No urine sample is needed

*Question: What is creatinine a waste product of?
A) Protein metabolism
B) Muscle metabolism
C) Fat metabolism
D) Carbohydrate metabolism

*Answer: B) Muscle metabolism

*Question: What is the most widely used endogenous clearance test?
A) Urea clearance
B) Inulin clearance
C) Creatinine clearance
D) Cystatin C

*Answer: C) Creatinine clearance

*Question: What is a disadvantage of creatinine clearance?
A) Creatinine is exogenous
B) Creatinine is secreted by tubules
C) Creatinine requires constant infusion
D) Creatinine is unstable in plasma

*Answer: B) Creatinine is secreted by tubules

*Question: What can cause falsely elevated creatinine in urine specimens?
A) Refrigeration
B) Bacterial breakdown at room temperature
C) Acidic pH
D) High protein diet consumed before collection

*Answer: B) Bacterial breakdown at room temperature

*Question: What is the normal GFR?
A) 80 mL/min
B) 100 mL/min
C) 120 mL/min
D) 150 mL/min

*Answer: C) 120 mL/min

*Question: What is the average body surface area used in GFR calculations?
A) 1.50 m²
B) 1.60 m²
C) 1.73 m²
D) 2.00 m²

*Answer: C) 1.73 m²

*Question: How many minutes are in a 24-hour collection period?
A) 1200 minutes
B) 1320 minutes
C) 1440 minutes
D) 1560 minutes

*Answer: C) 1440 minutes

*Question: What is the most accurate estimated GFR formula?
A) Cockcroft-Gault formula
B) MDRD-IDMS traceable formula
C) Schwartz formula
D) Jelliffe formula

*Answer: B) MDRD-IDMS traceable formula

*Question: At what GFR range are estimated GFR formulas most accurate?
A) Greater than 90 mL/min
B) 60-90 mL/min
C) Lower than 60 mL/min
D) All ranges equally

*Answer: C) Lower than 60 mL/min

*Question: What GFR defines Stage 5 CKD (end-stage renal disease)?
A) <30 mL/min/1.73 m²
B) <25 mL/min/1.73 m²
C) <20 mL/min/1.73 m²
D) <15 mL/min/1.73 m²

*Answer: D) <15 mL/min/1.73 m²

*Question: What GFR range defines Stage 3 CKD?
A) 60-89 mL/min/1.73 m²
B) 45-59 mL/min/1.73 m²
C) 30-44 mL/min/1.73 m²
D) 15-29 mL/min/1.73 m²

*Answer: B) 45-59 mL/min/1.73 m²

*Question: What is the earliest sign of kidney damage?
A) Decreased glomerular filtration
B) Loss of tubular reabsorption/concentrating ability
C) Increased protein excretion
D) Elevated serum creatinine

*Answer: B) Loss of tubular reabsorption/concentrating ability

*Question: Why can't GFR detect early renal disease?
A) The test is not sensitive enough
B) Remaining nephrons compensate by doubling capacity
C) GFR increases in early disease
D) Creatinine levels don't change early

*Answer: B) Remaining nephrons compensate by doubling capacity

*Question: What test measures the renal concentrating ability of the kidneys?
A) Creatinine clearance
B) Fishberg test
C) Fluid deprivation test
D) PSP test

*Answer: C) Fluid deprivation test

*Question: How long is the fluid deprivation period in the fluid deprivation test?
A) 6 hours
B) 8 hours
C) 12 hours
D) 24 hours

*Answer: C) 12 hours

*Question: What is the normal urine osmolarity after fluid deprivation?
A) 400 mOsm
B) 600 mOsm
C) 800 mOsm
D) 1000 mOsm

*Answer: C) 800 mOsm

*Question: What is the expected urine-to-serum osmolarity ratio after fluid deprivation?
A) 1:1
B) 2:1
C) 3:1 or greater
D) 5:1

*Answer: C) 3:1 or greater

*Question: What test differentiates neurogenic from nephrogenic diabetes insipidus?
A) Fluid deprivation test
B) ADH challenge
C) Fishberg test
D) Creatinine clearance

*Answer: B) ADH challenge

*Question: In neurogenic diabetes insipidus, what happens after ADH administration?
A) Urine osmolality remains

*Answer: B) Urine osmolality increases to >800 mOsm

*Question: In nephrogenic diabetes insipidus, what happens after ADH administration?
A) Urine osmolality increases to >800 mOsm
B) Urine osmolality remains <400 mOsm
C) U:S ratio normalizes to 3:1
D) Serum sodium decreases

*Answer: B) Urine osmolality remains <400 mOsm

*Question: What is the problem in neurogenic diabetes insipidus?
A) Kidneys don't respond to ADH
B) Excessive ADH production
C) Cannot produce ADH
D) Excessive water reabsorption

*Answer: C) Cannot produce ADH

*Question: What is the problem in nephrogenic diabetes insipidus?
A) Cannot produce ADH
B) Renal tubules do not respond to ADH
C) Excessive ADH production
D) Glomerular damage

*Answer: B) Renal tubules do not respond to ADH

*Question: What is the expected specific gravity after fluid deprivation in the Fishberg test?
A) ≥1.015
B) ≥1.020
C) ≥1.025
D) ≥1.030

*Answer: C) ≥1.025

*Question: In the Mosenthal test, which urine should have greater volume?
A) Night urine
B) Day urine
C) Both equal
D) Neither, volume is not measured

*Answer: B) Day urine

*Question: In the Mosenthal test, what is the expected specific gravity of night urine?
A) ≥1.010
B) ≥1.015
C) ≥1.020
D) ≥1.025

*Answer: C) ≥1.020