Renal2 Flashcards
How is Plasma Volume measured?
Radiolabeled Albumin
How is Extracellular Volume measured?
Inulin
The Glomerular Filtration Barrier filters according to what?
Size and Net Charge
What is the Glomerular Filtration Barrier composed of?
- Fenestrated capillary endothelium (size)
- Fused basement membrane with heparan sulfate (Negative charge)
- Epithelial layer consisting of podocyte foot processes
What barrier is lost in nephrotic syndrome? What is the result?
Charge Barrier
- Albuminuria
- Hypoproteinemia
- Generalized Edema
- Hyperlipidemia
Renal Clearance.
Volume of plasma from which the substance is completely cleared per unit time
-Cx = UxV/Px
Cx = clearance of x Ux = [urine] of x Px = [plasma] of x V = urine flow rate
What is used to calculate GFR?
Inulin clearance
- freely filtered
- neither reabsorbed nor secreted
What is normal GFR?
100 mL/min
What is an approximate measurement of GFR?
Creatinine clearance
-slightly overestimates GFR bc creatinine is moderately secreted by the renal tubules
Effective Renal Plasma Flow (ERPF) can be estimated using what?
PAH clearance
- filtered
- actively Secreted in proximal tubule
*ALL PAH entering the kidney is EXCRETED
Renal Blood Flow (RBF) equation.
RBF = RPF/(1-Hct)
*ERPF underestimates true RPF by ~ 10%
Filtration Fraction (FF) equation.
FF = GFR/RPF
What is a normal FF?
20%
Filtered load equation.
= GFR x Px
*Px = plasma concentration
Excretion rate equation.
= V x Ux
V = urine flow rate Ux = [urine] of x
