Renal MCQs – Physiology



Renal MCQs – Physiology

January 2007

1. Secretion of K+ by the distal tubule will be decreased by

a. Metabolic alkalosis

b. A high K+ diet

c. Hyperaldosteronism

d. Spironolactone administration

e. Thiazide diuretic administration

2. The following blood gas picture is most consistent with: pH = 7.56; pCO2 = 20mmHg; pO2 = 100mmHg; bicarb = 25mmol/(

a. Sepsis

b. Emphysema

c. Prolonged vomiting

d. Bicarbonate ingestion

e. 2 week residence at high altitude

3. The principal buffer in interstitial fluid is

a. Carbonic acid

b. Hb

c. Phosphate

d. Other proteins

e. Compounds containing histidine

4. Regarding absorption of Na+ in the proximal tubule

a. The proximal tubule reabsorbs 80% of the filtered sodium load

b. Absorption of Na+ causes increasing hypertonicity in the tubule lumen

c. Absorption is powered by the Na+/H+ ATPase

d. Shares a common carrier with glucose

e. All of the above are true

5. Which of the following agents does not cause contraction of the mesangial cells in the glomerulus?

a. Angiotensin I

b. Noradrenaline

c. Histamine

d. Dopamine

e. Vasopressin

6. The lower pH limit of the urine is

a. 1.0

b. 3.5

c. 4.5

d. 6.0

e. 7.0

7. ADH (vasopressin) secretion is increased by

a. Alcohol

b. Carbamazepine

c. ( extracellular fluid volume

d. Angiotensin I

e. Lying supine

8. With respect to the counter current system

a. The Loops of Henle act as counter current exchangers

b. Solutes diffuse out of vessels conducting blood toward the cortex

c. Water diffuses out of ascending vessels

d. Water diffuses into the collecting ducts

e. Counter current exchange is passive and can operate even if counter current multiplication ceases

9. Which of the following is most permeable to water?

a. Thin ascending Loop of Henle

b. Distal convoluted tubule

c. Thin descending Loop of Henle

d. Cortical portion of collecting tubule

e. Thick ascending limp of Loop of Henle

10. pH 7.16; pCO2 = 24mmHg; pO2 = 100mmHg; bicarbonate = 6mmol/(; K+ = 3.4mmol/(

Which of the following is MOST likely to cause the above picture

a. Cyanide poisoning

b. Hyperventilation

c. Liquorice ingestion

d. Addison’s disease

e. Conn’s syndrome

11. Metabolic alkalosis can be caused by all of the following EXCEPT

a. Hyperaldosteronism

b. Hyperventilation

c. Hypokalaemia

d. Volume depletion

e. Vomiting

12. The consumption of oxygen by the kidney

a. Decreases as blood flow increases

b. Is regulated by erythropoietin

c. Remains constant as blood flow increases

d. Directly reflects the level of sodium transport

e. Is greatest in the medulla

13. If the plasma concentration of a freely filterable substance that is neither secreted nor reabsorbed is 0.12gmg/ml, its urine concentration is 25mg/ml, and urine formation 1.0ml/min – the GFR is

a. 50ml/min

b. 125ml/min

c. 150ml/min

d. 200ml/min

e. 362ml/min

14. An increase in the concentration of plasma potassium causes an increase in

a. Release of renin

b. Secretion of aldosterone

c. Secretion of ADH

d. Release of natriuretic hormone

e. Production of Angiotensin II

15. GFR would be increased by

a. Constriction of the afferent arteriole

b. A decrease in afferent arteriolar pressure

c. Compression of the renal capsule

d. A decrease in the concentration of plasma protein

e. A decrease in renal blood flow

16. The greatest amount of hydrogen ion secreted by the proximal tubule is associated with

a. Excretion of potassium ion

b. Excretion of hydrogen ion

c. Reabsorption of calcium ion

d. Reabsorption of bicarbonate ion

e. Reabsorption of phosphate ion

17. All of the following comparisons between the distal nephron and the proximal tubule are correct EXCEPT

a. The distal nephron is less permeable to hydrogen ion than is the proximal tubule

b. The distal nephron is more responsive to aldosterone than is the proximal tubule

c. The distal nephron has a more negative intraluminal potential than does the proximal tubule

d. The distal nephron secretes more potassium than does the proximal tubule

e. The distal nephron secretes more hydrogen ion than does the proximal tubule

18. Urinary volume is increased by all of the following EXCEPT

a. Sympathetic stimulation

b. Diabetes insipidus

c. Diabetes mellitus

d. Increased renal arterial pressure

e. Infusion of mannitol

19. Which one of the following statements about aldosterone is correct?

a. It produces its effect by activating cAMP

b. It produces its effects by increasing membrane permeability to potassium

c. It causes an increased reabsorption of hydrogen ion

d. It has its main effect on the proximal tubule

e. It is secreted in response to an increase in BP

20. The ability of the kidney to excrete a concentrated urine will increase if

a. The permeability of the proximal tubule to water decreases

b. The rate of blood flow through the medulla decreases

c. The rate of flow through the Loop of Henle increases

d. The activity of the Na-K pump in the Loop of Henle decreases

e. The permeability of the collecting duct to water decreases

21. Which of the following returns closest to normal during chronic respiratory acidosis

a. Alveolar ventilation

b. Arterial PCO2

c. Arterial PO2

d. Plasma concentration of bicarbonate

e. Arterial concentration of hydrogen ion

22. Renal correction of hyperkalaemia will result in

a. Alkalosis

b. Increased secretion of HCO3-

c. Acidosis

d. Increased secretion of H+

e. Increased excretion of Na+

23. In controlling the synthesis and secretion of aldosterone – which of the following factors is LEAST important

a. Renin

b. Angiotensin II

c. Concentration of plasma Na+

d. ACTH

e. Concentration of plasma K+

24. Ammonia is an effective and important urinary buffer for which of the following reasons

a. Its production in the kidney ( during chronic alkalosis

b. The walls of the renal tubules are impermeable to NH3

c. The walls of the renal tubules are impermeable to NH4+

d. Its acid base reaction has a low pKa

e. None of the above

25. pH 7.67, PO2 120mmHg on O2; PCO2 60mmHg and bicarbonate 36mmol/l on a blood gas is indicative of

a. Respiratory alkalosis

b. Mixed metabolic and respiratory alkalosis

c. Metabolic acidosis

d. Respiratory acidosis

e. Metabolic alkalosis

26. The TMg for women (transport maximum for glucose) in the kidney is about

a. 75mg/min

b. 100mg/min

c. 150mg/min

d. 300mg/min

e. 500mg/min

27. A loss of function mutates in the gene of which of the following proteins is associated with nephrogenic diabetes insipidus

a. Aquaporin -1

b. Aquaporin -2

c. Aquaporin -3

d. Aquaporin -4

e. Aquaporin -5

28. Dehydration increases the plasma concentration of all of the following EXCEPT

a. Vasopressin

b. Angiotensin II

c. Aldosterone

d. Noradrenaline

e. Atrial natriuretic peptide

29. Calculate the anion gap from these results –

Na+ 142; K+ 3.5mmol/l; glucose 6mm0l/l; chloride 110mm0l/l; bicarbonate = 10mmol/l; urea = 7.0mmol/l

a. 10

b. 15

c. 17

d. 22

e. 29

30. Regarding water excretion

a. At least 87% of filtered water in kidney is reabsorbed

b. Urine concentration ca get as high as 1400mosm/kg

c. About 5% of filtered water is removed in the distal tubule

d. Aquaporin -1 plays a major role in water conservation, although it is unaffected by vasopressin

e. All of the above are correct

Renal Acid Base Physiology – Jan 05

Answers

1. C

2. E

3. A

4. E

5. D

6. C

7. B

8. B

9. C

10. A

11. B

12. D

13. D

14. B

15. D

16. D

17. E

18. A

19. B

20. B

21. E

22. C

23. D

24. C

25. E

26. D

27. B

28. E

29. D

30. E

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