Renal 2 Flashcards
The epithelium around glomerular capillaries is modified into…
podocytes (leaving slits through which filtration takes place)
mesangial cells
located between the capillaries that contract to alter blood flow (filtration)
the renal corpuscle
a triple filtration barrier
triple filtration barrier
-capillary endothelial cells
-basal lamina
podocyte endfeet
capillary endothelial cells are ________________ so things can pass through.
fenestrated
Which 3 pressures govern filtration from glomerular capillaries into the renal tubules?
- hydrostatic pressure
- colloid osmotic (oncotic) pressure
- Bowman’s capsule hydrostatic pressure
hydrostatic pressure
of blood in the glomerular capillaries favours filtration; ~55mmHg
colloid osmotic (oncotic) pressure
the pressure gradient due to the presence of plasma proteins and opposes filtration; ~30mmHg
Bowman’s capsule hydrostatic pressure
fluid pressure that opposes filtration; ~15mmHg
net filtration pressure is…
10mmHg (55-30-15)
The volume of fluid that filters from the glomerular capillaries into the Bowman’s capsules per day?
180L/day
The kidneys filter our entire plasma volume approximately…
60x/day
What 2 factors influence glomerular filtration rate (GFR)?
net filtration pressure and filtration coefficient
net filtration pressure
renal blood flow and blood pressure
filtration coefficient
the surface area of the glomerular capillaries available for filtration and permeability of interface between capillaries and Bowman’s capsule
GFR is primarily regulated by..
renal arterioles (afferent and efferent)
Autoregulation maintains a constant GFR when mean arterial blood pressure is…
between 80 and 180 mmHg
Renal blood flow’s resistance is determined by…
both the afferent and efferent arterioles (overall resistance)
What two auto-regulatory mechanism maintain a relatively stable GFR in the face of normal blood pressure fluctuations
- myogenic response of the afferent arterioles
- tubuloglomerular feedback
tubuloglomerular feedback
local control pathway in which fluid flow through the tubule portion of the nephron
macula densa cells
sense distal tubule flow and release paracrine that affect afferent arteriole diameter
granular cells
secrete renin, an enzyme involved in salt and water balance
Flow __________ passed macula dense cells
increases
Increased _____ has been shown to activate macula densa cells.
NaCl
Sympathetic activation only really alters GFR under conditions of…
hemorrhage or severe dehydration
What two hormones modulate arteriole resistance and filtration coefficient by acting on podocytes and/or mesangial cells?
angiotensin II (vasoconstrictor) and prostaglandins (vasodilator)
