A&P final Flashcards
What is the osmotic pressure on the afferent side of the glomerular capillary?
28mmHg
what is an important control point that the body manipulates to maintain a normal level of blood flow and filtration?
vascular resistance
If the kidney sees that blood flow is too low what happens?
afferent arteriole relaxes to increase blood flow
If renal blood flow is too high, how does the kidney respond?
the afferent arteriole constricts to prevent over profusion
If we keep a normal blood flow in the kidneys at the afferent arteriole, it should maintain a normal
GFR
because filtration is a result of blood flowing through the kidney
what type of graph would you see in autoregulation of blood flow in the kidneys
what is the significance of the slant in this graph?
It shows that kidney autoregulation isn’t perfect. If it was the line would be flat.
Instead, the kidneys retain fluid when pressure is low and decrease fluid when pressure is high which helps us manage blood pressure long term
How is the plasma oncotic pressure in the systemic capillary different than the plasma oncotic pressure in the kidney?
In the systemic capillary it doesn’t change from the arteriole end to the venule end, but in the kidney, because there is so much filtration in the middle of the glomerular capillaries, the oncotic pressure on the efferent end of the glomerular capillary is more concentrated(36mmHg) than the afferent side(28mmHg).
Why is the oncotic pressure higher on the efferent side of the glomerular capillary?
Because we are loosing so much fluid in the glomerular capillary it concentrates the fluid that is leaving through the efferent end
What is the osmotic pressure on the efferent side of the glomerular capillary?
36mmhg
what is the osmotic pressure in the middle of the glomerular capillaries?
32mmHg
What is the pressure in the Ptubule
Bowmans capsule
18mmHg
what is the protein osmotic pressure in the early part of the tubule?
0
Why don’t the proteins that are necessary for the cells that make up the tubule count towards the protein osmotic pressure in?
Because they are tethered and not floating around so they don’t have any protein osmotic pressure associated with them
How to solve for the NFP of renal tubule
60mmHg πglomerular capillary promotes filtration
-32mmHg πaverage glomerular capillary opposes filtration
-18mmHgPtubule opposes filtration
=
10mmHg NFP
The NFP of the renal tubule drives what?
125mL/min filtration rate in a 30 year old healthy adult
What is the Filtration coefficient sometimes associated with and what does it do?
NFP
helps us figure out what the filtration rate is.
How does NFP factor into the filtration rate?
You multiply the filtration coefficient (constant) by the NFP
If the renal filtration rate is 125mL/min and NFP is 10mmHg, what is Kf?
12.5 mL/min/mmHg
125mL/min/Kf X 10mmHg
Net filtration pressure times the filtration coefficient equal=
blood flow
what is the second arteriole that sits behind the glomerular capillaries?
efferent arteriole
efferent arteriole tone/contraction is used by the kidney to
fine tune the GFR
If you occlude outflow in the efferent arterioles that would
drive up pressure in the glomerular capillaries which would increase filtration
If GFR is low what does the kidney do to fix this?
constricts the efferent arteriole