1. RENAL
Dr;
bashardoust

2. Glomerular Filtration
Renal blood flow = 1.2 L/min
Renal plasma flow = 700 ml/min (60 % of RBF)
GFR = 125 ml/min = 180 L/day filtered plasma
Filtered fraction = GFR  RPF = 125  700 = 20%
Urine output = 1 ml/min or 1500 ml/day = 1% of filtered plasma

3. Renal Anatomy Functional unit is the nephron Functions of nephron
Approximately 1.25 million/kidney
80% are cortical – short loop of Henle
20% are juxtamedullary – loop of Henle projects into medulla
Cortical nephrons only dilute urine
Juxtamedullary nephrons dilute and concentrate urine
Functions of nephron
Glomerular filtration
Tubular reabsorption
Tubular secretion

4. Filtration, Reabsorption, Secretion
A: filtered, no reabsorption or secretion - inulin, creatinine
B: filtered, some reabsorption - electrolytes
C: filtered, complete reabsorption - glucose, amino acids
D: filtered, plus additional secretion - K+, H+

6. Anatomy:
Cap. loops
J.G.App.
DCT
Afferent Arteriole Efferent

7. Glomerular Filtration:
Collagen IV
Laminin
Fibronectin
Entactin
etc.
BLOOD
Proteins
3.6nm/70,000MW
Glomerular Capillary Lumen
L.R.I
L.D.
L.R.E
Foot Process
Podocyte
(Visceral epithelium)
GBM +
Plasma -
Proteins
FILTRATE
Bowman’s Capsule Space

9. Azotemia Renal Failure
Table Laboratory Findings in Acute Renal Failure
Index
Prerenal
Azotemia
Oliguric Acute
Renal Failure
BUN/PCr Ratio
>20:1
10-15:1
Urine sodium (UNa), meq/L
<20
>40
Urine osmolality, mosmol/L H2O
>500
<350
Fractional excretion of sodium
<1%
>2%
FENa =
UNa * PCr * 100
PNa * UCr
Urine/plasma creatinine (UCr/PCr)
NOTE: BUN, Blood urea nitrogen; PCr, plasma creatinine; UNa, urine sodium concentration; PNa, plasma sodium concentration; UCr, urine creatinine concentration.