Renal Blood Flow and Glomerular Filtration

Question 1

Filtration fraction

Answer 1

GFR/RPF (renal plasma flow)

Question 2

Changes in the afferent arteriolar resistance change GFR and RPF

Answer 2

synchronously (they go up or down together)

Question 3

Changes in the efferent arteriolar resistance change GFR and RPF

Answer 3

dysynchronously (they go in opposite directions, e.g. if efferent pressure goes up, GFR goes up and RPF goes down)

Question 4

Autoregulation maintains …….. over a wide range of ………. by changing ………..

Answer 4

GFR/RPF (FF) ; pressures ; resistance

Question 5

Measuring GFR requires a substance whose …… depends entirely on ……..

Answer 5

excretion ; filtration

Question 6

GFR can be calculated clinically by this equation

Answer 6

GFR = (Uin X V)/Pin

urine inulin times volume divided by plasma inulin

Question 7

Cockroft Gault is an equation for…..

MDRD is an equation for…..

Answer 7

creatinine clearance

GFR

Question 8

What’s the problem with creatinine clearance measurements?

Answer 8

Creatinine is secreted by the proximal tubule

Question 9

In cases of kidney disease the error between creatinine clearance and inulin clearance…
why?

Answer 9

grows (the amount secreted goes up)

Question 10

Equation for fractional excretion

what is this commonly used for?

Answer 10

FEx = amount excreted/amount filtered x 100

sodium, phosphorus and magnesium