Quantitative Renal Phys or Eval of Renal Fuction (Rao) Flashcards Preview

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Flashcards in Quantitative Renal Phys or Eval of Renal Fuction (Rao) Deck (28)
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1
Q

Mass flow =

formula

A

concentration x rate of flow

expression od solute movements as a function of time

2
Q

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

A

rate of intake + rate of production - metabolism

3
Q

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

A

Rate of production

4
Q

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

rate of output =

A

rate of intake

5
Q

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

A

F: only in urine

6
Q

What are the 3 routes for kidney output?

A

renal vein, lymphatic, urine

7
Q

Mass flow in the kidney =

A

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

8
Q

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

A

plasma flow

9
Q

In a healthy nephron:

Filtration + secretion =

A

reabsorption + excretion

*input = output

10
Q

Filtration rate =

A

GFR X Px

11
Q

Excretion rate =

A

UF x Ux

12
Q

What are the 3 parameters that quantify kidney function?

A

GFR
plasma clearence of solutes
renal blood flow

13
Q

Why is inulin the model for measuring kidney function?

A
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
14
Q

What is the formula for GFR?

A

GFR = UF x Ux/Px

15
Q

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

A

clearance

16
Q

What effect does increased reabs have on clearance

A

decreases it

17
Q

What effect does increased secretion have on clearance

A

increases it

18
Q

What does a low clearance for a solute indicate?

A

it is reabs

19
Q

What does a high clearance for a solute indicate?

A

it is secreted

20
Q

What is the formula for extraction ratio?

A

Ex ratio = (Ax -Vx)/Ax

21
Q

What does the extraction ratio measure?

A

the % of substance removed from the plasma

22
Q

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

A

low

23
Q

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

A

high

24
Q

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

A

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

25
Q

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

A

~1

*90-95% clearance

26
Q

T or F: Cx of PAH = RPF

A

T: bc PAH is cleared completely

27
Q

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

A

decreases

28
Q

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

A

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