Renal MCQs – Physiology

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Renal MCQs – Physiology January 2007

1. 2. Secretion of K+ by the distal tubule will be decreased by a. b. c. d. e. Metabolic alkalosis A high K+ diet Hyperaldosteronism Spironolactone administration Thiazide diuretic administration The following blood gas picture is most consistent with: pH = 7.56; pCO 2 = 20mmHg; pO 2 = 100mmHg; bicarb = 25mmol/  a. b. c. d. e. a. b. c. d. e. The principal buffer in interstitial fluid is a. b. c. d. e. Sepsis Emphysema Prolonged vomiting Bicarbonate ingestion 2 week residence at high altitude Carbonic acid Hb Phosphate Other proteins Compounds containing histidine Regarding absorption of Na+ in the proximal tubule The proximal tubule reabsorbs 80% of the filtered sodium load Absorption of Na+ causes increasing hypertonicity in the tubule lumen Absorption is powered by the Na+/H+ ATPase Shares a common carrier with glucose All of the above are true

5. 9. 10. 8. 6. 7. Which of the following agents does not cause contraction of the mesangial cells in the glomerulus? a. b. c. d. e. Angiotensin I Noradrenaline Histamine Dopamine Vasopressin The lower pH limit of the urine is a. b. c. d. e. 1.0 3.5 4.5 6.0 7.0 ADH (vasopressin) secretion is increased by a. b. c. d. e. Alcohol Carbamazepine  extracellular fluid volume Angiotensin I Lying supine With respect to the counter current system a. b. c. d. e. The Loops of Henle act as counter current exchangers Solutes diffuse out of vessels conducting blood toward the cortex Water diffuses out of ascending vessels Water diffuses into the collecting ducts Counter current exchange is passive and can operate even if counter current multiplication ceases Which of the following is most permeable to water? a. b. c. d. e. a. b. c. d. e. Thin ascending Loop of Henle Distal convoluted tubule Thin descending Loop of Henle Cortical portion of collecting tubule Thick ascending limp of Loop of Henle pH 7.16; pCO 2 = 24mmHg; pO 2 = 100mmHg; bicarbonate = 6mmol/  ; K+ = 3.4mmol/  Which of the following is MOST likely to cause the above picture Cyanide poisoning Hyperventilation Liquorice ingestion Addison’s disease Conn’s syndrome

14. 15. 16. 11. 12. 13. Metabolic alkalosis can be caused by all of the following EXCEPT a. b. c. d. e. Hyperaldosteronism Hyperventilation Hypokalaemia Volume depletion Vomiting The consumption of oxygen by the kidney a. b. c. d. e. Decreases as blood flow increases Is regulated by erythropoietin Remains constant as blood flow increases Directly reflects the level of sodium transport Is greatest in the medulla 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. b. c. d. e. 50ml/min 125ml/min 150ml/min 200ml/min 362ml/min An increase in the concentration of plasma potassium causes an increase in a. b. c. d. e. Release of renin Secretion of aldosterone Secretion of ADH Release of natriuretic hormone Production of Angiotensin II GFR would be increased by a. b. c. d. e. a. b. c. d. e. Constriction of the afferent arteriole A decrease in afferent arteriolar pressure Compression of the renal capsule A decrease in the concentration of plasma protein A decrease in renal blood flow The greatest amount of hydrogen ion secreted by the proximal tubule is associated with Excretion of potassium ion Excretion of hydrogen ion Reabsorption of calcium ion Reabsorption of bicarbonate ion Reabsorption of phosphate ion

17. 20. 21. 18. 19. All of the following comparisons between the distal nephron and the proximal tubule are correct EXCEPT a. b. c. d. e. The distal nephron is less permeable to hydrogen ion than is the proximal tubule The distal nephron is more responsive to aldosterone than is the proximal tubule The distal nephron has a more negative intraluminal potential than does the proximal tubule The distal nephron secretes more potassium than does the proximal tubule The distal nephron secretes more hydrogen ion than does the proximal tubule Urinary volume is increased by all of the following EXCEPT a. b. c. d. e. Sympathetic stimulation Diabetes insipidus Diabetes mellitus Increased renal arterial pressure Infusion of mannitol Which one of the following statements about aldosterone is correct? a. b. c. d. e. a. b. c. d. e. It produces its effect by activating cAMP It produces its effects by increasing membrane permeability to potassium It causes an increased reabsorption of hydrogen ion It has its main effect on the proximal tubule It is secreted in response to an increase in BP The ability of the kidney to excrete a concentrated urine will increase if The permeability of the proximal tubule to water decreases The rate of blood flow through the medulla decreases The rate of flow through the Loop of Henle increases The activity of the Na-K pump in the Loop of Henle decreases The permeability of the collecting duct to water decreases Which of the following returns closest to normal during chronic respiratory acidosis a. b. c. d. e. Alveolar ventilation Arterial PCO Arterial PO 2 2 Plasma concentration of bicarbonate Arterial concentration of hydrogen ion

22. 23. 24. 25. 26. 27. Renal correction of hyperkalaemia will result in a. b. c. d. e. Alkalosis Increased secretion of HCO Acidosis Increased secretion of H+ Increased excretion of Na + 3 - In controlling the synthesis and secretion of aldosterone – which of the following factors is LEAST important a. b. c. d. e. Renin Angiotensin II Concentration of plasma Na ACTH Concentration of plasma K + + Ammonia is an effective and important urinary buffer for which of the following reasons a. b. c. d. e. Its production in the kidney  during chronic alkalosis The walls of the renal tubules are impermeable to NH The walls of the renal tubules are impermeable to NH Its acid base reaction has a low pKa None of the above 3 4 + pH 7.67, PO 2 120mmHg on O 2 ; PCO 2 60mmHg and bicarbonate 36mmol/l on a blood gas is indicative of a. b. c. d. e. Respiratory alkalosis Mixed metabolic and respiratory alkalosis Metabolic acidosis Respiratory acidosis Metabolic alkalosis The TMg for women (transport maximum for glucose) in the kidney is about a. b. c. d. e. 75mg/min 100mg/min 150mg/min 300mg/min 500mg/min A loss of function mutates in the gene of which of the following proteins is associated with nephrogenic diabetes insipidus a. b. c. d. e. Aquaporin -1 Aquaporin -2 Aquaporin -3 Aquaporin -4 Aquaporin -5

28. 29. 30. a. b. c. d. e. Dehydration increases the plasma concentration of all of the following EXCEPT a. b. c. d. e. Vasopressin Angiotensin II Aldosterone Noradrenaline Atrial natriuretic peptide 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. b. c. d. e. 10 15 17 22 29 Regarding water excretion At least 87% of filtered water in kidney is reabsorbed Urine concentration ca get as high as 1400mosm/kg About 5% of filtered water is removed in the distal tubule Aquaporin -1 plays a major role in water conservation, although it is unaffected by vasopressin All of the above are correct

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Renal Acid Base Physiology – Jan 05 Answers

1. C 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

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