Flashcards in Renal Clearance Deck (44)
What are the units of clearance?
Volume per unit time
What are the 3 processes in the nephron?
Resorption of the Substance into Blood
Secretion of the Substance into Tubule
What are the renal units for concentration?
What are the renal units for flow?
What are the renal units for load?
Concentration x in Arterial Plasma
Concentration x in Venous Plasma
Concentration x in Urine
Renal Blood Flow
Renal Plasma Flow
Glomerular Filtration Rate
Urine Flow Rate
What is the kidney input load equal to?
Pax + RPFa
What is the kidney output load equal to?
(Pvx * RPFv) + (Ux * V)
If urine flow rate V>0mL/min then how are the values of the RFPa and RFPv affected?
RPFa > RPFv
What is the equation for conservation of mass in regards to renal function?
Pax + RPFa = (Pvx * RPFv) + (Ux * V)
What are the loads that enter the tubule?
F - filtered load
S - secreted load
What are the loads that leave the tubule?
R - reabsorbed load
E - excreted load
What is the filtered load equal to?
Pax * GFR
What is the excreted load equal to?
Ux * V
What is clearance?
It is defined as the volume of plasma completely cleared of any substance in one minute
What is the range of clearance?
0 to RPF (maximum)
What is the RPF in terms of the cardiac output?
RPF is around 25% of the cardiac output
How much of the RPF does the kidney filter?
20% -> this is the GFR
What is the formula for clearance?
Cx = Ux * (V/Px)
Px - plasma concentration of x
Why is the venous return ignored in clearance?
Venous blood is returned to the body
What happens if Cx < GFR?
Substance x is filtered and reabsorbed
What happens if Cx = GFR?
x is only filtered
What happens if Cx > GFR?
x is filtered and secreted