Study BIOL 472 Topic 13 Flash Cards

 
Pile Management Card
BIOL 472 Topic 13

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PAH
-unique in that clearance > GFR
-actively secreted
-as long as PAH [] is below threshold, all is cleared
-if above threshold, some remains in peritubular caps
splay
-threshold pt not absolute for all nephrons
-some at 350, some at 400, etc.
glucose
-Tm= tubular transport maximum
-375mg/min (max amt that can be reabsorbed)
-if below this, all is reabsorbed and clearance is 0
-at threshold and above, excess appears in urine
-splay
inulin
-freely filtered
-doesn't alter GFR
-not absorbed, secreted, metabolized
-amt filtered/min = amt excreted/min
-GFR= clearance
-inulin clearance good measure of GFR
-must be infused
creatinine
-used to measure GFR clinically (like inulin) but infusion necessary
-breakdown product from muscle metabolism
-easily filtered, some secretion
clearance eq
-C= ([U] x V)/[P]

[U]= urine []
V= urine flow rate
[P]= plasma []

excretion rate= [U] x V (mg/min)
clearance
-rate of exretion of a substance divided by its plasma []
-mL/min

-efficiency calc
-explains ability of kidneys to excrete a substance based on plasma []
filtration fraction
GFR/RPF (renal plasma flow)
-usually 15-20% of entering plasma is filtered
renal blood flow
RBF= RPF/(1-HCT)

HCT usually 37%
Glomular filtration rate
-amt plasma filtered per unit time
-100-125 mL/min is normal
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