Page 627 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Renal ` RENAL—PhysioLogy Renal ` RENAL—PhysioLogy SeCTIOn III 583

Filtration Filtration fraction (FF) = GFR/RPF. GFR can be estimated with creatinine
Normal FF = 20%. clearance.
Filtered load (mg/min) = GFR (mL/min) RPF is best estimated with PAH clearance.
× plasma concentration (mg/mL). Prostaglandins Dilate Afferent arteriole (PDA).
Angiotensin II Constricts Efferent arteriole
(ACE).

Prostaglandins preferentially
NSAIDs dilate a†erent arteriole Bowman capsule
∆
( RPF, GFR, so no FF) (parietal layer)
Bowman space Podocytes
A
(visceral layer)

P
Juxtaglomerular BS
erent arteriole
cells π
GC
Filtered Excreted
Macula densa P
GC
π Reabsorbed Secreted
Distal renal BS
tubule Peritubular
capillary
Net filtration pressure
Endothelial cells = (P + π ) – (P + π )
BS
GC
BS
GC
Mesangial Basement
cells membrane
E erent arteriole
Angiotensin II preferentially
ACE inhibitors constricts e†erent arteriole
( RPF, GFR, so FF)

Changes in glomerular dynamics
GFR RPF FF (GFR/RPF)
Afferent arteriole constriction   —
Efferent arteriole constriction   
 plasma protein concentration  — 
 plasma protein concentration  — 
Constriction of ureter  — 
Dehydration   

FAS1_2019_14-Renal.indd 583 11/7/19 5:42 PM