glomerular Flashcards
renal blood flow =
20% of CO per min (high flow for filtration, rather than metabolism)
glomerular filtration: two types of forces
1) hydrostatic pressures
- pressure due to volume of fluid
- pushes fluid away
2) colloid osmotic pressures
- osmotic pressure due to protein
- pulls fluid towards
4 forces for net filtration pressure
glomerular hydrostatic pressure= blood pressure (+50)
blood colloid osmotic pressure = albium (-25)
capsular hydrostatic pressure = pressure of filtrate already present (-15)
capsular colloid osmotic pressure = no protein in capsular space (+0)
net filtration pressure = 10mmHg
filtration fraction
what proportion/percentage of the kidneys plasma flow is filtered?
How much RPF is filtered
20% of RPF is filtered
80% remains in the glomerular capillaries
glomerular filtration rate (GFR)
how much plasma is filtered per minute
GFR equation
glomerular filtration rate = renal plasma flow x filtration fraction
renal filtered load
how much of a substance in plasma is filtered per minute
filtered load equation
filtered load = GFR x solute plasma conc.
renal clearance
how much plasma is cleared of a substance per minute
clearance of creatinine
= volume of plasma filtered per minute (GFR)
clearance of medications and toxins
= volume of plasma flowing through the kidneys per minute = RPF
clearance of glucose
= no plasma is cleared of glucose = 0
clearance of sodium
very small volume of plasma per minute
clearance equation
= (conc. of X in urine x volume of urine produced per unit time)/ conc. of X in plasma
