Hosam Mohamed-
c
Which type of nephron has the lowest renin content?
a) superficial
b) mid cortical
c) juxtamedullary
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Vasa Recta
-straight, long capillaries that provide oxygen and nutrients to the medulla
-
facilitate exchange of substances between blood flowing in & blood flowing out of the medulla
The descending & ascending vasa recta are group into vascular bundles to do what?
-
constrict renal blood vessels and cause a fall in renal blood flow
Sympathetic nerve fibers in the kidney do what?
-
mechanical stretch; chemicals; parencyma
Afferent renal nerves are stimulated by ________ or by various ______ in the renal ________.
-
c
What kind of cells are considered renal sensor elements that detect changes in distal tubular fluid composition and transmit signals to the glomerular vascular elements?
a) Granular cells
b) extra-glomerular mesangial cells
c) macula densa cells
d) mesangial cells
-
b
Which cells are continuous with mesangial cells of the glomerulus
and may transmit information from macula densa cells to granular cells?
a) Granular cells
b) extra-glomerular mesangial cells
c) macula densa cells
d) mesangial cells
-
a
Which cells are modified vascular smooth muscle cells with an epitheliod appearance; located primarily on afferent arterioles close to the glomerulus?
a) Granular cells
b) extra-glomerular mesangial cells
c) macula densa cells
d) mesangial cells
-
synthesize & release renin
Granular cell function?
-
release adenosine which causes vasoconstriction; this slows the filtration rate and prevents water loss, increasing blood pressure
How does the JGA respond to a drop in blood pressure?
-
Renin
-causes more sodium to be reabsorbed----leads to water being reabsorbed as well.
-increases blood volume which leads to an increase in blood pressure
-
c
Renin is released when?
a) before adenosine
b) in conjunction with adenosine
c) after adenosine
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RAAS
-is the compensatory system for hypovolemia, hyponatremia, and hypotension
-
arteriole vasoconstriction & reduces the rate of blood filtration
What are angiotensins 2 primary functions?
-
excretion=filtration - reabsorption + secretion
What is the formula for Excretion or Urine formation?
-
glomerular filtration, tubular reabsorption, tubular secretion
What are the three processes involved in forming urine?
-
glomerular filtration
-involves the ultrafiltration of plasma in the glomerulus
-
urinary space of bowman capsule then downstream to tubule lumen
Where does filtrate go after filtration?
-
renal blood flow
______ is roughly 25% of the cardiac output.
-
d
What percentage of renal blood flow is filtered and makes up the primary urine?
a) 25%
b) 15%
c) 5%
d) 10%
-
a
Where is blood flow the highest in the kidney?
a) cortex
b) outer medulla
c) inner medulla
-
helps maintain hyperosmolar environment in the kidney
What is the purpose behind the low blood flow in the inner medulla ?
-
b,c
What causes an increase in the GFR?
a) increased hydraulic pressure in the Bowman's capsule
b) the area or amount of glomerular capillaries
c) increased hydraulic pressure in glomerular capillaries
d) increased colloid osmotic pressure
-
a,b,d
What causes a decrease in GFR?
a) increased hydraulic pressure in the bowman's capsule
b) decreased permeability
c) increased pressure in glomerular capillaries (hydrostatic pressure)
d) increased colloid osmotic pressure
-
hydrostatic pressure; arterial blood pressure
The _______ in the glomerular capillaries is directly dependent on ________ and is the decisive factor for the normal regulation of the GFR.
-
myogenic response, raas, tubuloglomerular feedback
What kidney mechanisms maintain blood pressure and a constant GFR?
-
true
Autoregulation is an intrinsic property of the kidneys. T/F?
-
upstream
When blood pressure is raised or lowered, vessels _______ of the glomerulus constrict or dilate to maintain constant glomerular blood flow and capillary pressure.
-
myogenic mechanism & tubuloglomerular feedback
Renal autoregulation is comprised of two mechanisms; what are they?
-
high; low
Vessel radius is small when blood pressure is _______ & vessel radius is large when blood pressure is ______.
-
Myogenic mechanism
-an increase in pressure stretches blood vessel walls and opens stretch-activated cation channels in smooth muscle cells
-
macula densa
Tubuloglomerular feedback primarily operates through the ______ and detects changes in hydrostatic pressure.
-
glomerular hyperfiltration & increased fluid load on the tubule
Increased hydrostatic pressure can lead to : _______ & ________
-
releases atp, thromboxane, and adenosine to cause vasoconstriction of distal tubule
How does the macula densa regulate hydrostatic pressure?
-
tubuloglomerular feedback mechanism
-a negative-feedback system that stabilizes renal blood flow and GFR
-
increased NaCl reabsorption causes depolarization of cells; resulting in vasoconstriction and returning GFR to normal
How does the tubuloglomerular feedback mechanism work?
-
adenosine; juxtaglomerular interstitium
ATP is metabolized to _______ in the ___________.
-
Adenosine
-combines with receptors in the afferent arteriole and causes vasoconstriction, and blood flow and GFR are lowered to a more normal value.
-
false
Angiotensin II is a vasoconstrictor agent. T/F?
-
changes in local renin activity
The sensitivity of the tubuloglomerular feedback mechanism is altered by _____________.
-
false; depends on the substance
Tubular transport (reabsorption, secretion) is always active. T/F?
-
nonselective; selective
Glomerular filtration is _______ while Tubular transport is _______.
-
sodium; potassium
Na-K-ATPase pump transports 3 __________ out of the cell and 2 _________ into the cell.
-
Colloid osmotic pressure
-pressure that accumulates from albumin's negative charge; tries to keep water in the blood
-decreases GFR
-
Capsular Hydrostatic Pressure
- pressure that comes from the filling of the bowman capsule
-decreases GFR
-
Glomerular hydrostatic pressure
-pressure that drives fluid out of the glomerulus and into the bowman capsule.
