Loop of Henle

Question 1

What is the main function of the Loop of Henle?

Answer 1

Reabsorption

Question 2

What is the isosmotic level of plasma in the proximal tubules?

Answer 2

300mOsmol/L

Question 3

What part of the loop of Henle is essential for water balance?

Answer 3

Juxtamedullary nephrons

Question 4

What is the maximum concentration of urine that the kidneys can produce?

Answer 4

1200-1400mOsmoles/l

Question 5

What concentration of waste levels need to be excreted every day and therefore what volume of water must accompany this?

Answer 5

600mOsmol/L

500ml water needed to excrete this

Question 6

What is the minimum concentration of urine the kidneys can excrete in a day?

Answer 6

30-50mOsmol/L

Question 7

What two aspects of the loop of Henle make it a counter current multiplier?

Answer 7

The ascending limb of the loop of Henle actively co-transports Na+ and Cl- ions out of the tubule lumen into the interstitium. The ascending limb is impermeable to H2O.
The descending limb is freely permeable to H2O but relatively impermeable to NaCl.

Question 8

What is the interstitial gradient created by the removal of sodium chloride?

Answer 8

300-700mOsmol/L

Question 9

How does the diuretic frusemide work?

Answer 9

Stops the removal of NaCl from the tubules therefore an interstitial gradient can not be created so only an isotonic urine is produced.

Question 10

What is the function of the vasa recta?

Answer 10

Provide O2 for medulla but must not disturb gradient.

Removes volume from the interstitium, up to 36l/day.