11/11 Flashcards
What is the osmotic pressure on the afferent side of the glomerular capillary?
28mmHg
If we wanted to maintain relatively constant blood flow in the kidney what would we have to have?
autoregulation through the afferent arterioles constricting and relaxing
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
if GFR is too high what does the kidney do to fix this?
relaxes the efferent arteriole
What is the BP at the end of the efferent arteriole?
18mmHg
The afferent arteriole drops blood pressure by _______mmHg from the renal artery to the glomerular capillaries
40mmHg of resistance in the afferent arteriole
100mmHg-60mmHg=40mmHg
The efferent arteriole drops blood pressure by ______mmHg from the glomerular capillary to the end of the efferent arteriole
42mmHg of resistance in the efferent arteriole
60mmHg-18mmHg=42mmHg
The efferent arteriole has the highest _______ in all the blood vessels in the kidney
vascular resistance
__________% of everything that is filtered is reabsorbed
99%
__________% of everything that is filtered gets excreted out
1-2%
What is the reabsorption route from the cells that line the tubule and the interstitial matrix?
Through or between cells (water and small stuff) that make up the walls of the tubule
After something is filtered, if we want to hold on to it, how does it get into the blood?
through or between the cells that line the tubule-> matrix-> peritubular capillaries
cv system
What is the matrix intermediary place between tubules and vessels?
Name and what is is made of:
renal interstitium
proteins
ions/electrolytes
larger energy compounds
The net reabsorption pressure in the peritubular capillaries is high or low?
high
The net filtration pressure in the peritubular capillaries is high or low?
low
plasma oncotic pressure at peritubular capillaries is
πperitubular capillary
32mmHg
BP in the peritubular capillaries is
13mmHg
πRenal ISF is
15mmHg
physical fluid pressure of Peritubular ISF
PISF
6mmHg
NFP of renal ISF
-10mmHg
Net reabsorption pressure of the renal ISF
10mmHg
Vast majority of blood that moves through the kidney stays in the
cardio vascular system and passes through the efferent arteriole
What part of the blood is filtered in the kidney?
the plasma
What percent of the blood that moves through the kidney gets filtered?
a little over 10%
125mL/min /1100mL=11.36%
How much of the plasma gets filtered in the kidney?
1/5
Though which vessel does the blood plus everything that gets reabsorbed leave the kidney?
renal vein
How is the renal tubule shaped?
It wraps around and has a very convoluted shape
Which part of the nephron empties into our bladder?
renal tubule
ureter
bladder
The process by which we remove things from the body via the urine is termed what?
excretion
What is the excretion formula?
Filtration
-reabsorption
+secretion
Secretion is when the body:
physically pumps things into the renal tubule to get rid of them
The pathway that secretion takes is ______ of reabsorption
reverse