Flashcards in 10. Renal clearance Deck (10):
volume of plasma from which the substance is completerly cleared per unit ( from renal)
renal clerance - calculation
Cx = Ux . V / Px
Cx = clearance of x ( ml / min)
Ux = urine concentration of x ( mg / ml)
Px = plasma concentation of X ( mg / ml)
V = urine flow rate (ml/ min(
if renal clearance equals / smaller than GFR
Cx smaller : if smaller net tubular reasbsorption of X
Cx bigger : net tubular secretion of X
Cx = GFR : no net secretion or reabsorpition
Inulin clearance can be used to ... ( why )
calculate GFR because it is freely filtered an is neithere reabsorder nor secreted
What is clearance? With what unit of measurement is it expressed?
• The volume of plasma from which a substance is completely cleared per unit of time; measured in milliliters per minute (mL/min)
• What is the formula for calculating the clearance of substance X, the volume of plasma cleared completely of X per unit of time?
Clearance of X = Urine concentration of X (mg/mL) × urine flow rate (mL/min) divided by plasma concentration of X (mg/mL) (Cx = Ux × V/Px)
• If renal clearance is less than the glomerular filtration rate of substance X, there is net tubular ____ (reabsorption/secretion) of X.
• X is measured in a patient. Plasma level (Px) is 100 mg/mL, urine level (Ux) 200 mg/mL, urine flow (V) 1 mL/min. What is X's clearance (Cx)?
Cx (mL/min) = (Ux × V)/Px = (200 mg/mL × 1 mL/min)/100 mg/mL = 2 mL/min
• In a patient, Y's clearance (Cy) is 3 mL/min. He voids 3 mL/min. Plasma level (Py) is 5 mg/mL. What is the urine level of substance (Uy)?
Knowing Cy = (Uy × V)/Py: Uy = (Cyy