Glomerular Filtration & Renal Blood Flow Flashcards
The external baroreceptor reflex results in a hormonally-mediated _____.
constriction of the arterioles
______ rises rapidly when MAP exceeds its auto-regulatory range.
Pgc
What are granular cells?
specialized smooth muscle cells in the afferent arterioles that secrete renin
In the equation, GFR = K(Pgc - Pt - πgc), what is K?
- the product of the specific hydraulic conductivity “ρ” times the total surface area “A” of all the glomeruli in the kidneys
- K= ρA
Pgc is very tightly regulated by the process of ______.
glomerular capillary autoregulation
Neural stimulation of the afferent arteriole also causes the increased release of _____ from the _____ cells of the JG apparatus.
renin; granular
This is a sheet of epi cells with many projections that acts as a molecular sieve.
podocytes
The renin/angiotensin axis is stimulated by detection of reduced arteriolar pressure by intrarenal baroreceptors thought to reside on the _____ cells themselves.
granular
If a decline in MAP is sensed by the main arteries, what happens?
a baroreceptor reflex = activity of the renal sympathetic nerve increases to cause arteriole constriction
What produces renal prostaglandins?
renal interstitial cells
What are podocytes?
a sheet of epi cells with many projections that acts as a molecular sieve
Name 2 forces that oppose glomerular filtration.
- backpressure from Bowman’s capsule (Pt)
- the net osmotic force from serum proteins (COP or πgc)
The flow of the filrate first passes through the ______.
fenestrated glomerular capillary endothelium
The renin/angiotensin axis is stimulated by detection of ______ by ______ thought to reside on the granular cells themselves.
reduced arteriolar pressure; intrarenal baroreceptors
The coordinate constriction of arterioles during hypovolemia is mediated by which baroreceptors?
the external and renal baroreceptors
What is the glomerular basal lamina?
a thick, negatively charged basement membrane secreted by the endothelial and epithelial cells consisting of mucoproteins
Where are renal interstitial cells found?
in the medulla between the pyramids
Neural stimulation of the _____ also causes the increased release of renin from the granular cells of the JG apparatus.
afferent arteriole
What is the normal filtration fraction value?
0.2
What is the equation for GFR?
GFR = K(Pgc - Pt - πgc)
What is the size limit for substances trying to freely pass through the glomerulus?
60,000 daltons
Why are prostaglandins secreted in the kidney if they counteract the action of the hypovolemic constriction response?
to maintain adequate renal blood flow, specifically at the afferent arteriole, by blunting vasoconstriction
The renal solution to hypovolemia: GFR is maintained by ______.
co-ordinate constriction of the afferent and efferent arterioles
What is the regulating “valve” to keep the renal blood flow constant, under normal conditions?
the afferent arteriole
The ______ is stimulated by detection of reduced arteriolar pressure by intrarenal baroreceptors thought to reside on the granular cells themselves.
renin/angiotensin axis
As for any capillary bed, filtration out of the glomerulus is driven by the _______.
blood pressure
The podocytes help create and support the ____.
basal lamina
When are prostaglandins secreted? What do they do?
they’re secreted in response to angiotensin II and have a local dilatory effect on the renal arterioles
The glomerular capillaries are covered by the so-called _____ cells.
mesangial
These are specialized smooth muscle cells in the afferent arterioles that secrete renin.
granular cells
