Quantitative Renal Physiology or Evaluation of Renal Function

Question 1

What is the equation for mass flow?

Answer 1

Mass Flow = Concentration x Volume Flow

Question 2

What are the routes of flow in the kidney?

Answer 2

Input - renal artery

Output - urine, renal vein, lymphatics

Question 3

What is the equation for filtration rate?

Answer 3

Filtration Rate = GFR x Px

Question 4

What is the equation for excretion rate?

Answer 4

Excretion Rate = UF x Ux

Question 5

What substance is used as a model to measure kidney function?

Answer 5

Inulin (not produced in body, not metabolized, excreted only by kidney)

Question 6

What is the equation for plasma inulin concentration?

Answer 6

P in = Infusion rate / Output rate

Question 7

What is the equation that relates GFR and inulin?

Answer 7

GFR = UF x U in / P in

Question 8

Define clearance.

Answer 8

Volume of plasma that is completely cleared of a substance by the kidneys per unit time.

Question 9

What is the equation for extraction ratio?

Answer 9

Ex Ratio = (Ax - Vx) / Ax
Ax = arterial [ ]
Vx = renal venous [ ]

Question 10

What substance do we use to calculate effective renal plasma flow and what is the equation?

Answer 10

Para aminohippurate

C pah = (UF x U pah) / P pah

Question 11

What happens to GFR and creatine plasma [ ] following a nephrectomy?

Answer 11

Sudden drop in GFR that returns to original value

Increase in plasma creatinine concentration