Renal Function Tests - Rao

Question 1

What is mass flow?

Answer 1

Expression of solute movement as a function of time

Question 2

Mass flow =

Answer 2

concentration x volume flow, equalling amount per minute

Question 3

How do you measure mass flow in the kidney?

Answer 3

Arterial Intake = output to veins, lymph, urine

Question 4

Plasma concentration of X=

Answer 4

intake/output

Question 5

Rate of inulin filtration would be equal to

Answer 5

GFR x plasma concentration of inulin

Question 6

Clearance formula for anything

Answer 6

(UF*[U])/[P]

Question 7

What is the extraction ratio?

Answer 7

Percent of substance removed from the plasma

Question 8

What does reabsorption do to the extraction ratio?

Answer 8

Lower

Question 9

What does secretion do to the extraction ratio?

Answer 9

Raise

Question 10

What is the extraction ratio formula?

Answer 10

= (A-V)/A, basically comparing arterial and venous differences

Question 11

What substance is used to measure RPF?

Answer 11

PAH, because it is cleared almost completely in 1 pass since it is secreted in addition to being filtered

Question 12

What is the relationship between plasma creatinine and GFR?

Answer 12

It is NOT linear; it is logarithmic

Question 13

Explain what happens to plasma inulin, creatinine clearance in a uninephrectomy

Answer 13

GFR drops in half. Plasma inulin concentration doubles but the amount of inulin excreted into urine per unit time stays the same.