Quantitative Renal Phys or Eval of Renal Fuction (Rao)

Question 1

Mass flow =

formula

Answer 1

concentration x rate of flow

expression od solute movements as a function of time

Question 2

For solutes that are ingested and metabolized… (i.e. glucose)
rate of output =

Answer 2

rate of intake + rate of production - metabolism

Question 3

For solutes that are produced only by metabolism… (i.e uric acid, urea)
rate of output =

Answer 3

Rate of production

Question 4

For solutes that are not producedin the body… (i.e NaCl)

rate of output =

Answer 4

rate of intake

Question 5

T or F: Urea can be excreted in sweat and feces.

Answer 5

F: only in urine

Question 6

What are the 3 routes for kidney output?

Answer 6

renal vein, lymphatic, urine

Question 7

Mass flow in the kidney =

Answer 7

rate of flow in renal vein + lymphatics + urine x the conc in enal vein + lymphatics + urine

Question 8

Water input to the kidney is the same as ______ into the kidney

Answer 8

plasma flow

Question 9

In a healthy nephron:

Filtration + secretion =

Answer 9

reabsorption + excretion

*input = output

Question 10

Filtration rate =

Answer 10

GFR X Px

Question 11

Excretion rate =

Answer 11

UF x Ux

Question 12

What are the 3 parameters that quantify kidney function?

Answer 12

GFR
plasma clearence of solutes
renal blood flow

Question 13

Why is inulin the model for measuring kidney function?

Answer 13

it is not produced in the body
it is not metabolized 
it is excreted only in the kidney
not secreted by tubule
not reabs by tubule

Question 14

What is the formula for GFR?

Answer 14

GFR = UF x Ux/Px

Question 15

What is the volume of plasma that is completely cleared of the substance by the kidneys per unit time?

Answer 15

clearance

Question 16

What effect does increased reabs have on clearance

Answer 16

decreases it

Question 17

What effect does increased secretion have on clearance

Answer 17

increases it

Question 18

What does a low clearance for a solute indicate?

Answer 18

it is reabs

Question 19

What does a high clearance for a solute indicate?

Answer 19

it is secreted

Question 20

What is the formula for extraction ratio?

Answer 20

Ex ratio = (Ax -Vx)/Ax

Question 21

What does the extraction ratio measure?

Answer 21

the % of substance removed from the plasma

Question 22

WIll a substance that is reabs have a high or low extraction ratio?

Answer 22

low

Question 23

WIll a substance that is secreted have a high or low extraction ratio?

Answer 23

high

Question 24

T or F: If a substance X is cleared completely from the plasma the clearance will equal the venous plasma concentraton

Answer 24

F: Cx = total renal plasma flow (when a substance is cleared completely)

Question 25

What is the extraction ratio of PAH (para amino hippuric acid)

Answer 25

~1

*90-95% clearance

Question 26

T or F: Cx of PAH = RPF

Answer 26

T: bc PAH is cleared completely

Question 27

If GFR increases, plasma creatinine will (inc, decrease, stay the same).

Answer 27

decreases

Question 28

T or F: decreasing GFR by 1/2 has very little effect on plasma creatinine levels

Answer 28

F: there is a mechanism for compensation of dec GRF… but after 50% you will see an sharp increase in plasma creatinine bc the threshold will be reached