Renal Physiology

Question 1

What is reabsorbed in the proximal tubule.

Answer 1

65% Na+, 65% H20, urea, glucose.

Question 2

The proximal pushes 90% of what molecule into the blood.

Answer 2

Hydrogen carbonate.

Question 3

Is the filtrate at the proximal tubule isotonic, hypertonic or hypotonic.

Answer 3

Isotonic

Question 4

Does the medullary interstitial osmolality get saltier the more hypotonic, hypertonic or isotonic we go down the medulla.

Answer 4

Hypertonic (saltier)

Question 5

Why does the medullary interstitial become more saltier.

Answer 5

NKCC2 transporter pumps sodium, 2 chlorides and potassium of lumen filtrate into tubule cells of the ascending limb.
The specific channels for each ion in the cell will push out Na+ and Cl-. Increasing the osmolality.
Some K+ leak out and some K+ pushed back in the lumen.

Question 6

What is important about K+ being used back into the lumen of ascending limb (Mg2+/Ca2+)

Answer 6

K+ being pushed in the lumen causes the inner side of the membrane of the ascending limb to depolarise causing Mg2+ and Ca2+ to undergo paracellular transport.

Question 7

Ascending limb is permeable to water

(A) True
(B) False

Answer 7

(B) False.

Question 8

At the descending limb was is able to be reabsorbed.

Answer 8

Water via AQP1 channels.
Small amounts of urea, sodium (Na+) and other ions are reabsorbed.

Question 9

Where does the most water absorption occur in the renal tubules.

Answer 9

At loop of henle

Question 10

How is water reabsorption driven at the loop of henle?

Answer 10

By the counter-current multiplier system.

Question 11

What triggers aldosterone production?
a) hypernatremia
b) hypokalemia
c) angiotensin-I
d) hyperkalemia

Answer 11

D