Renal Phys--> look of Henle

Question 1

What makes up the Loop and Henle?

Answer 1

Thin descending limb
Thin ascending limb
Thick ascending limb

Question 2

Which limb is permeable to water and not solute? Which is vice versa?

Answer 2

Descending

Ascending, respectively

Question 3

What is the Na:water absorption in the loop? What does this create/

Answer 3

25%:10%

• creates different osmolality in filtrate than plasma
• lumen goes from 300 to 100 mOsms after the loop

Question 4

If you go from 300 to 100 mOsms are you diluting or concentrating?

Answer 4

Diluting

Question 5

What is the NKCC2 transporter?

Answer 5

Transports 
Na
K
2CL
- Found in thick ascending limb 
- all sites must be occupied to work

Question 6

What does 2Cl to Na ratio create in the lumen? What does this cause?

Answer 6

Creates slight positive charge in lumen

- pushes Ca, Mg and Na out of lumen filtrate via paracellular transport

Question 7

What is being recycled in the loop? What percent? By what transporter?

Answer 7

K+
90%
ROMK
- Critical to keep NKCC2 channel running. Because all sites must be occupied to work

Question 8

What is a Bartton Channel?

Answer 8

Channel which Cl- leaves cell via basolateral side

- Via down conc. gradient

Question 9

What is another way Cl can leave the cell?

Answer 9

K+ synporter on basolateral side

Question 10

how much Na does the NKCC channel absorb? Ca? Mg?

Answer 10

25% of filtered load

• 20% Ca
• 50-60% Mg

Question 11

What upregulates NKCC?

Answer 11

AgII

ADH

Question 12

What is Bartter Syndrome?

Answer 12

Any disorder affecting transporters in the thick ascending limb

• either directly or indirectly affects NKCC2
• HypoNa+ leads to hypovolemia
• Hypokalemia
• normal to elevated urinary Ca excretion
• metabolic alkalosis
• Growth retardation

Question 13

What is the conc. of Na after the loop?

Answer 13

about 50mM

Question 14

What is something that can downregulate the NKCC channel?

Answer 14

Ca sensitive receptors

- to much calcium can downregulate NKCC