GFR increases in pregnancy by 25 50 from 120mlmin to 160 170mlmin with a

Gfr increases in pregnancy by 25 50 from 120mlmin to

This preview shows page 111 - 114 out of 144 pages.

GFR increases in pregnancy by 25-50% from 120ml/min to 160-170ml/min with a parallel increase in renal plasma flow. GFR is altered by posture and is reduced in the supine or upright position compared to a lateral position. Increased salt intake increases GFR * · Plasma concentrations of creatinine, uric acid and urea are decreased in pregnancy * Question 52 The phosphate buffer system A Is not effective in the extracellular space B Is not effective in the intracellular space C Is less effective in renal tubular fluid than in the extracellular fluid D Is more effective in intracellular fluid than in extracellular fluid E Is only effective if pH is below 6.8 A(Correct answer: D) Explanation PHOSPHATE BUFFER SYSTEM ***** Made up of Na2HPO4 (weak base) and NaHPO4 (weak acid) Has a pK of 6.8 Low concentration of buffers in extracellular fluid therefore less important than bicarbonate buffer Higher concentration in renal tubular fluid. In addition, pH of tubular fluid is closer to pK of phosphate buffer system - therefore more important buffer Higher concentration in intracellular fluid and pH is closer to pK - becomes more important Question 53 A 23 year old woman presents at 6 weeks gestation with a 48 hours history This Copy is for Dr. Mohamed ElHodiby
Image of page 111
of severe nausea and vomiting. Her acid-base status is likely to show A A metabolic acidosis with normal anion gap B A metabolic acidosis with increased anion gap C A metabolic alkalosis with hyperchloraemia D A metabolic alkalosis with hypokalaemia E A metabolic acidosis with hypokalaemia A(Correct answer: D) Explanation METABOLIC ALKALOSIS ***** · Less common than metabolic acidosis · Associated with potassium or chloride depletion Caused by · Vomiting -causes hypochloraemic alkalosis with hypokalaemia and potassium loss in urine. * · Urine is acidic despite systemic alkalosis - when alkalosis is associated with volume depletion, bicarbonate is not excreted. · Excretion of bicarbonate only occurs with restoration of extracellular fluid volume · Diuretics -loop diuretics especially. Associated with hypochloraemia and hypokalaemia * Question 54 A 23 year old woman presents at 6 weeks gestation with a 48 hours history of severe nausea and vomiting. Her acid-base status is likely to show A A metabolic acidosis with acidic urine B A metabolic alkalosis with alkaline urine C A metabolic alkalosis with acidic urine D A metabolic acidosis with alkaline urine E A compensated respiratory acidosis with acidic urine A(Correct answer: C) Explanation Same as of Question 53 A Bicarbonate ions are secreted into the proximal tubule B The majority of filtered bicarbonate is reabsorbed in the proximal tubule C Carbonic anhydrase plays a key role in the reabsorption of bicarbonate ions D Hydrogen ions are absorbed from the tubular lumen coupled to sodium secretion E Hydrogen ions are secreted into the tubular lumen coupled to potassium absorption This Copy is for Dr. Mohamed ElHodiby
Image of page 112
A(Correct answer: B) Explanation RENAL ACID-BASE REGULATION ***** · Bicarbonate : 90% of filtered bicarbonate is reabsorbed in the proximal tubule. Depending
Image of page 113
Image of page 114

You've reached the end of your free preview.

Want to read all 144 pages?

  • Fall '18
  • mot
  • Nephron, Dr. Mohamed ElHodiby

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes