Question

21. Bicarbonate is reabsorbed into the epithelial cells of the proximal convoluted tubule as ________________.

1. HCO3-
2. CO2
3. H2CO3
4. Carbonic anhydrase

22. Loop diuretics block the Na+/ 2Cl-/K+ cotransporter on the ascending loop of henle. How does this reduce water reabsorption?

1. By preventing the reabsorption of sodium ions, water is not reabsorbed from the ascending loop of henle
2. It causes hyperkalcemia which stimulates Aldosterone secretion, thereby, indirectly causing the excretion of sodium, potassium and water.
3. It abolishes and/or reduces the osmotic gradient between the descending loop of henle and the ascending vasa recta
4. It increases the sodium ion concentration in the loop of Henle which stimulates the release of ADH causing an increase in water excretion.

23.During World War II when there was a shortage of penicillin, an anti-gout medication, Probenecid was administered with penicillin. Why?

1. Probenecin blocks the filtration and secretion of Penicillin
2. Probenecid blocks the filtration of Penicillin
3. Although penecillin is filtered, Probenecid blocks the organic anion transporter on the basoalateral membrane of the proximal tubule preventing secretion and urine loss of penecillin
4. Probenecin blocks organic cation transporters on the apical membrane of the proximal tubule, preventing the secretion of penicillin

24.What type of compensation would you expect in a patient with metabolic alkalosis?

A. A compensatory respiratory acidosis caused by a decrease in respiratory rate

B. A compensatory metabolic acidosis caused by an increase loss of bicarbonate in the urine

C. A compensatory respiratory alkalosis caused by an increased in respiratory rate

D. A compensatory alkalosis caused by an increased loss of H+ in the urine

Answer 1

21.answer is B

the diagram given below is of ion exchange in nephron

In another diagram given below is the transport of bicarbonate ion

22. Answer is C. ( This was a really nice Ques )

Explanation..

Option a is wrong because Loop diuretics act on the Na+-K+-2Cl− symporter In the thick ascending limb of the loop of Henle. Thus they inhibit sodium, chloride and potassium reabsorption. This inhibition of loop diuretics is done by competing for the Cl− binding site. So this option isn't totally wrong but to the context of ques it isn't the answer.

Option b is wrong because loop diuretics causes hypokalemia

Option c is right because in the absence of proper working of sodium potassium chloride symporter the concentration gradient which is required to maintain to sustain the counter current multiplier mechanism isn't available.

Option D is wrong

23. Option c is right

24. Both a and b are correct

But more effective is respiratory mechanisms of slowing down the breathing rate to retain CO2. So if only one answer is acceptable then the answer is a