05.06 - RBF, GFR (Rao) - PP, Lecture Guide, No reading, Not watched Flashcards
What effect on net filtration pressure does lower urinary tract obstruction have?
Increase Pbs –> Decrease GFR
How does sympathetic activation affect Resistance, RPF, GFR
Constriction of Aff and Eff -> Dec RPF and Pg -> Dec GFR
How does Ang 2 affect renal arteriolar resistance and GFR
Induces renal arteriolar constriction and reduces GFR, paradoxically opposing auto regulation
How does Sympathetic affect Kf
Decrease Kf by stimulating mesangial cells -> Dec GFR
How does DM affect GFR
Decreases Kf, so decreases GFR
Higher NaCl at MD =
Inc Afferent Arteriolar R -> Dec GFR
Proteinuria can either be from barrier failure or ___
Abnormal Circulating Protein (breakdown of tissue, production of abnormal proteins)
How does dec Cl in DT affect Renin
Inc Renin -> Inc Ang II, etc
Net Filtration Pressure =
(Pg + Pibs) - (Pig + Pbs)
How does Uretral Obstruction affect GFR, FF?
Reduce GFR and thus FF
Kf =
Filtration Coefficient = Hydraulic Conductivity x SA of Glomerular Capillaries
Mechanism of GFR Autoreg: Dec GFR ->
Dec Cl in distal tubule -> MD -> Dec Arteriolar Resistance -> Inc GFR
When is Autoregulation more important vs Sympathetics
Autoregulation dominates under normal conditions; Sympathetics only under severe ECFV loss
How does Endothelin affect GFR
Constrict Arterioles (aff and eff) -> Dec GFR
How do sympathetics control renin
B1 receptors stimulate renin in JG cells
2 locations where hydrostatic pressure drops
Afferent Arteriole; Efferent Arteriole/Peritubular Capillary
Size of Albumin
6nm or 60 angstroms
How does Low Capillary Flow affect FF, Pig, Net filtration pressure, GFR
Inc FF -> Inc Pig -> Dec Net Filtration Press -> Dec GFR
T/F: Autoregulation in kidney depends on sympathetic input?
False, isolated in kidney
GFR =
Kf x Net filtration pressure
Lower NaCl at MD =
Dec Afferent Arteriolar R -> Inc GFR
Two Theories of Autoregulation
Myogenic, Tubuloglomerular Feedback
Adrenaline vs Endothelin 1 on resistance
Adrenaline is perferentially for Afferent, Endothelin does both
How does decreased efferent resistance affect GFR, RPF
Decreased GFR, Increased RPF
How does Adrenaline affect GFR
Constrict Arterioles (preferentially afferent) -> Dec GFR
Normal GFR is __ mL/min, ___ L/day
130 mL/min; 180 L/day
Size of glomerular pores
8nm or 80 angstroms
How does increased efferent resistance affect GFR, RPF?
Increase GFR, Decrease RPF
Hydraulic Conductivity x SA of Glomerular Capillaries
Kf (Filtration Coefficienty)
How does Renal Artery Stenosis affect RPF, FF?
Reduces RPF, thus increases FF
Anions and Cations in Glomerulus vs Ultrafiltrate
4-5% more anions in ultrafiltrate and 4-5% less cations - Gibbs Donnan effect
What is the filtration fraction?
GFR / RPF
How does decreased Afferent resistance affect GFR, RPF
Increase GFR, RPF
How does increase Afferent resistance affect GFR, RPF?
Decrease GFR, RPF
When does sympathetic response act on nephron?
Overrides autoregulation in severe ECFV loss
What does the Tubuloglomerular feedback mechanism sense
NaCl at Macula Densa
Alternate route that Inc GFR -> Inc Arterolar R
Inc GFR -> Inc Cl in DT -> Na-K-Cl in MD cells -> Release ATP or AA metabs -> SM contraction -> Inc Art R
How does NO affect GFR?
Decreased Vascular R -> Inc GFR
How does pressure affect renin release
Increased pressure in afferent arteriole inhibits renin release from JG cells; Vice versa
How do PG’s affect GFR?
Decreased Vascular R -> Inc GFR
The kidneys receive what percent of cardiac output?
20%
Source of Endothelin that affects GFR?
Damaged endothelial cells
Mechanism of GFR Autoreg: Inc GFR ->
Inc Cl in distal tubule -> MD -> Inc Arteriolar Resistance -> Dec GFR
