Flashcards in Renal Blood Flow Deck (37):
essentially free of blood cells and proteins, but otherwise identical to plasma
sum in all nephrons
-therefore, index of functioning renal mass
layers of glomerular membrane
inside > out
fenestrated capillary endothelium - highly permeable to water, dissolved solutes
glomerular basement membrane - collagen, proteoglycans with anionic charge
podocyte epithelium - slit pores between podocytes restrict large molecules
glomerular slit diaphragm
-CD2AP and CD2-associated proteins
-nephrin molecules - are diaphragm
charge and filterability?
cationic is filtered more readily
anionic is filtered less readily
loss of negative charge on basement membrane before noticeable changes in renal structure
results in more filtration of proteins
GFR = ?
Kf x P-UF
Kf ultrafiltration coefficient (htdraulic conductivity times the surface area)
P-UF capillary ultrafiltration pressure
3 factors of GFR?
1 - hydraulic conductivity (Lp) of glomerular membrane (porosity)
2 - surface area of filtration
3 - Capillary ultrafiltration pressure
determined by hydrostatic and colloid osmotic pressure in glomerular capillaries
P-BC - (P-GC + osmotic-GC) = P-UF**
osmotic-BC is approximately zero (no protein)
as move along glomerular capillary?
increased oncotic GC pressure
net ultrafiltration pressure decreases as move along
glomerular and peritubular starling forces?
mesangial cell contraction
changes in P GC
P-GC determined by what
renal arterial BP
afferent arteriolar resistance
efferent arteriolar resistance
contraction of mesangial cells?
shorten capillary loop
determined by changes in systemic arterial pressure P-A, afferent arteriolar resitance R-A, and efferent arteriolar resistance R-E
afferent arteriolar constriction
lower renal blood flow
efferent arteriolar constriction
pooling of blood in glomerular capillaries
increased systemic arterial pressure?
increased afferent arteriolar constriction?
increased efferent arteriolar constrition?
efferent arteriolar dilation?
afferent arteriolar dilation?
maintains GFR over MAP range of 80-170 mmHg
receives most RBF
-medulla receives less via vasa recta
constriction of afferent
decreased RBF and GFR
granular cells then secrete renin
causes ANG II increases
acts to restore blood pressure (systemic vasoconstriction)
promotes arteriolar constriction (efferent > afferent)
raises BP, may stabilize GFR
also stimulates Na+ reabsorption in proximal tubule, ascending loop of henle, distal convoluted tubule, collecting duct