Renal MCQs
1. Regarding the nephron:
a. Glucose is mostly reabsorbed in the distal tubule – Almost completely in the PCT with aa.s and
HCO3b. Water is mostly reabsorbed in the collecting tubule under the influence of vasopressin (ADH) – 6070% in PCT, 15% in LoH, only 20% enters the DCT (impermeable to water) -> CD
c. Insulin is mostly reabsorbed in the distal tubule – inulin is freely filtered and not reabsorbed,
secreted or metabolised (Hence used to measure GFR)
d. Sodium is mostly reabsorbed in the distal tubule – 3% under influence of aldoseterone
e. None of the above is correct
2. Regarding Na reabsorption:
a. Most Na is reabsorbed in the distal tubule – 60% PCT, mostly via Na-H co-transport
b. Na is electrogenic in the ascending limb of the loop of Henle – the energy for the apical membrane
Na2ClK co-tansporter is the low intracellular Na (via the basolateral NaK ATPase)
c. Decreased NaCl concentration at the distal tubule decreases GFR
d. The thin portion of the loop of Henle is impermeable to Na – this is incorrect, the thin ascending
limb is very permeable to NaCl, however there is no active transport of Na+ in the thin portion of the
loop of Henle
e. ANP increases Na reabsorption - decreases
3. Regarding the renal handling of H+:
a. The distal tubule predominantly secretes hydrogen via a proton pump – true, via ATP driven pump
in (intercalcated) I-cells as opposed to PCT via Na-H co-transporation
b. NH3 plays a minor part in tubular buffering – important role
c. The pK of the ammonia system is 10.0 – pK’ = 9.0 (ratio of NH3 : NH4+ at pH 7 = 1:100)
d. Titratable acidity provides a measure of the total amount of acid secreted – no because doesn’t
account for H2CO3 -> H2O and CO2 or the NH4+ (pK’ = 9.0) and titratable acidity is amount require
to pH 7.4 – i.e. will still be buffering
e. Aldosterone has no effect on renal pH – aldosterone increases H+/K+ secretion in exchange for
Na reabsorbtion
4. A factor that increases renal tubular calcium reabsorption is:
a. Decreased PTH
b. Decreased blood pressure
c. Decreased plasma phosphate
d. Metabolic
e. Increased ECF volume
5. concerning the glomerular filtration rate (GFR), it:
a. is approximately 250ml/min in an average sized normal man – 125ml/min
b. exceeds the clearance of a substance if there is net tubular reabsorption – tough question, but I
think this is actually correct: the actual GFR will be higher – the subsequent reabsorption will reduce
the clearance of the substance. If calculating GFR with net reabsorption you will get a figure that is
incorrectly low (in the case of Cr there is excretion, and the figure is incorrectly high, balanced by the
inaccurately high measurement of plasma Cr due to nonspecific chromogens)
c. is independent of the size of the renal capillary bed – dependent (Kf is the glomerular ultrafiltration
co-efficient = permeability x surface area)
d. is greater for anionic than for cationic molecules of equal size - negatively charged anions are
repelled
e. is maintained despite a fall in systemic pressure below 90mmHg - the lower limit of autoregulation
is 90mmHg
6. Under normal circumstances the urinary concentration of:
a. Sodium is higher than that of plasma – very little Na -> urine
b. Glucose is equal to plasma – very little glucose -> urine
c. Urea is approximately 900mg/dl – low urea, high ammonia
d. Creatinine is higher than that of urea – it is ammonia that remains in the urine
e. Sodium is approximately 150meq/L
7. Regulation of potassium excretion in the kidney involves:
a. Secretion by proximal tubule cells – secretion by late DCT and CD (600 filtered – 560 reabsorbed
+ 50mmol secreted = 90mmol = daily intake)
b. Exchange with Na+ on the tubular side via an active pump – on basolateral side by NaK ATPase
c. Passive reabsorption in the ascending limb of the loop of Henle
d. Active reabsorption in the proximal tubules – via Na2ClK co-transporter, 65% PCT, 25% TALH and
CD.
e. Active exchange with Ca2+ via a K+/Ca2+ exchange – w/ Na
8. Regarding renal handling of hydrogen ion, which of the following is INCORRECT?
a. Acetazolamide decreases tubular secretion – carbonic anhydrase inhibitor
b. Aldosterone increases distal tubular secretion – aldosterone increases Na absorption, K/H
secretion
c. Much more acid secretion occurs in proximal than distal tubule – true, mostly buffered by HCO3-,
also NH3
d. Lowest tubular fluid pH achievable is 4.5 – correct, the limiting pH
e. Secondary active transport mechanism operates in distal tubule – no secretion is via active proton
pump ATP driven
9. Sodium reabsorption in the kidney is:
a. Actively transported in the thin portions of the loop of Henle
b. Coupled to the movement of glucose and amino acids in the distal tubule
c. Decreased by atrial natriuretic peptide
d. Reabsorbed against its concentration gradient
e. Independent of chloride absorption
10. GFR:
a. Is higher per body surface area in women – 10% lower
b. Increases with a decrease in MAP
c. Normally 80% of filtrate is reabsorbed
d. Is accurately estimated by serum creatinine
e. Decreases with ureteral obstruction – true, due to increased tubular hydrostatic pressure
11. In the distal tubular cells:
a. K+ secretion is mainly by active transport mechanisms
b. K+ secretion is decreased in acidosis
c. K+ secretion is increased when Na+ delivery to the tubule is decreased
d. Loop diuretics will cause decreased K+ secretion
e. K+ is reabsorbed by the Na+/K+/2Cl- transporter
12. The diuretic action of water is due to:
a. Production of osmotic diuresis
b. Inhibition of vasopressin secretion
c. Supplying the acid(H+) load
d. Decrease tubular reabsorption of Na+ and increase GFR
e. Inhibition of Na+/K+/2Cl- cotransport in the medullary thick ascending limb of the loof of Henle
13. Sodium excretion is increased by:
a. Hyperkalaemia
b. Hyperaldosteronism
c. Thiazide diuretics
d. Lactic acidosis
e. Cortisol
14. sodium is mostly reabsorbed in
a. collecting system
b. ascending limb of the loop of Henle
c. distal convoluted tubule
d. proximal convoluted tubule
e. descending limb of the loop of Henle
15. The maximum urine acidity is pH of
a. 4.5
b. 5.0
c. 6.8
d. 7.0
e. 7.4
16. renal blood flow is
a. 10% of cardiac output
b. not influenced by prostaglandins
c. reduced by sympathetic stimulation
d. not maintained in the denervated kidney
e. not affected by acetylcholine
17. Glomerular filtration rate is increased by:
a. Angiotensin II
b. Vasopressin
c. Hypotension
d. Dopamine
e. Noradrenaline
18. Renal blood flow
a. Can be measured using inulin
b. Constitutes about 35% of cardiac output
c. Can be determined by applying the Fick principle
d. Is increased by norepinephrine
e. Is equal to the calculated effective renal plasma flow
19. Regarding renal blood flow:
a. Dopamine causes renal vasoconstriction
b. Glomerular capillary pressure is about 40% of systemic areterial pressure
c. Noradrenaline mainly constricts efferent arterioles
d. The kidneys receive 15% of cardiac output
e. Prostaglandins increase blood flow in the renal cortex and medulla
20. Under normal conditions the percentage of Na reabsorbed in 24 hours is:
a. 60
b. 80
c. 90
d. 95
e. 99
21. With regard to K+ excretion by the kidney
a. Most filtered K+ is passively reabsorbed in the proximal tubules – actively via Na2ClK CT
b. K+ is secreted into tubular fluid by distal tubular cells – true ~50mmol/day is passively secreted
c. The rate of K+ secretion is inversely proportional to the flow rate through the distal nephron –
proportional to the flow via P (principal cells), with high flow the K+ conc is low -> secretion
d. K+ movement in the distal tubules is an active process – passive secretion
e. K+ secretion mirrors H+ secretion in the distal tubule – they compete for secretion, in acidosis
there will be reduced K+ secretion
22. Regarding the bladder
a. The first urge to void is at 400ml – 150ml
b. Intravesical pressures can remain constant over a range of volumes
c. Voiding reflex is dependent on sympathetic control
d. Parasympathetic reflex controls external urethral sphincter
e. ?
23. With regard to the kidney
a. Has optimum autoregulation over a range of 60-100mmHg – 90-220mmHg
b. Medullary blood flow is greater than cortical blood flow – opposite (the medulla more suspectible)
c. Prostaglandins decrease medullary blood flow - true
d. Prostaglandins increase cortical blood flow - true
e. ?
24. With regard to the renal handling of K+
a. It is reabsorbed proximally and secreted into the distal tubule
b. It is absorbed and secreted proximally
c. ?
d. ?
e. ?
25. The absorption of Na+ in the proximal tubule:
a. Reabsorbs 80% of the filtered sodium load
b. Causes increasing hypertonicity
c. Is powered by Na+/H+ ATPase
d. Shares a common carrier with glucose
e. All of the above
26. With regard to osmotic diuresis
a. Urine flows are much less than in a water diuresis
b. Vasopressin secretion is almost zero
c. The concentration of the urine is less than plasma
d. Increased urine flow is due to decreased water reabsorption in the proximal tubule and loop of
Henle
e. Osmotic diuresis can only be produced by sugars such as mannitol
27. Renal acid secretion is affected by all of the following except:
a. PaCO2
b. K+ concentration
c. Carbonic anhydrase
d. Aldosterone
e. Ca2+
28. glucose reabsorption in the kidney is
a. a passive process
b. closely associated with K+
c. resembles glucose reabsorption in the intestine
d. occurs predominantly in the distal tubule
e. is the same in all nephrons
29. Which of the following is the most permeable to water?
a. Thin ascending limb of loop of Henle
b. Distal convoluted tubule
c. Thin descending limb of loop of Henle
d. Cortical portion of collecting tubule
e. Thick ascending limb of loop of Henle
30. With regard to urea
a. It moves actively out of the proximal tubule
b. It plays no part in the establishment of an osmotic gradient in the medullary pyramids
c. All of the tubular epithelium is impermeable to urea except for the inner medullary portion of the
collecting duct
d. A high protein diet reduces the ability of the kidney to concentrate urine
e. Vasopressin has no effect on the movemnt of urea across tubular epithelium
31. With a fall in systemic blood pressure
a. GFR falls more than renal plasma flow
b. There is efferent arteriolar constriction
c. The filtration fraction falls
d. There is no efferent arteriolar constriction
e. GFR does not change
32. What is the filtration fraction of the kidney (GFR/RBF)
a. 0.1
b. 0.2 - 0.16 – 0.2, increases with decreased BP
c. 0.3
d. 0.4
e. 0.5
33. The osmolarity of the pyramidal papilla is
a. 400
b. 800
c. 1200
d. 1600
e. 2000
34. What is the major stimulus for the secretion of ADH?
a. ?
b. ?
c. ?
d. ?
e. hyperosmolarity
35. Which of the following would be best used for measuring GFR?
a. Radiolabelled albumin
b. Inulin
c. Deuterium oxide
d. Tritium oxide
e. Mannitol
36. Given the following values, calculate GFR. Plasma PAH 90, urine PAH 0.3, plasma inulin 0.25,
urine inulin 35, urine flow 1ml/min, Hct 40%
a. 120
b. 150
c. 180
d. 240
e. 400
37. Where in the renal tubules does the intratubular and interstitial osmolality hold the same
values
a. Thick ascending loop of Henle
b. Thin descending loop of Henle
c. Distal convoluted tubule
d. Collecting duct
e. None of the above
38. With respect to the GFR:
a. It can be equated to creatinine clearance
b. ?
c. ?
d. ?
e. ?
39. With respect to the renal handling of potassium
a. ?
b. ?
c. ?
d. potassium is reabsorbed actively in the proximal tubule
e. ?
40. In the kidneys sodium is mostly reabsorbed with
a. Chloride
b. Bicarbonate
c. Glucose
d. Potassium
e. Calcium