Final Exam Lecture 3 Flashcards
Plasma Oncotic Pressure of Afferent Arteriole/Glomerular Capillaries Beginning
28 mmHg
Plasma Oncotic Pressure in Middle of Glomerular Capillaries
32 mmHg
Plasma Oncotic Pressure in the End of the Glomerular Capillaries/Beginning of Efferent Arteriole
36 mmHg
Hydrostatic/Hydraulic/Physical Fluid Pressure of Tubule/Bowman’s Capsule
18 mmHg
Plasma Osmotic Pressure of Tubule/Bowman’s Capsule
0 mmHg
NFP in Tubule/Bowman’s Capsule
10 mmHg
Normal GFR
125 mL/min
End of Efferent Arteriole Hydrostatic/Hydraulic/Physical Fluid Pressure
18 mmHg
Peritubular Capillaries Hydrostatic/Hydraulic/Physical Fluid Pressure
13 mmHg
Peritubular Capillaries Plasma Oncotic Pressure
32 mmHg
Renal Interstitium Interstitial Fluid Colloid Osmotic Pressure
15 mmHg
Renal Interstitium Hydrostatic Pressure
6 mmHg
NFP of Peritubular Capillaries
-10 mmHg
Reabsorption Pressure of Peritubular Capillaries
10 mmHg
What % of materials are absorbed by the kidneys?
*What % is excreted
99%
*1-2%
What is the blood flow to the kidneys in mL/min?
1100 mL/min
What is the blood flow to the kidneys in L/min
1.1L/min
What % of Total Blood Flow to the kidneys is the GFR
10%
Low and High Limits for Renal Autoregulation
50-150 mmHg
What is a normal urine output?
1 mL/min
What is a normal Filtration Fraction [FF]
19-20%
What is the formula for Filtration Fraction?
GFR/RPF
How do you calculate RPF?
*Give normal Values
*What is a normal RPF
If HCT is 0.40, the math is 0.60 x 1100 mL/min = 660
*660
What does GFR = ?
*Equation with values
GFR = Kf * NFP
GFR = 12.5 * 10 mmHg
In the kidney, what is the control point for normal filtration and blood flow?
The Afferent Arteriole
If you have decreased blood flow to the kidney, what will the afferent arteriole do?
Dilate to increase the blood flow
If you have increased blood flow to the kidney, what will the afferent arteriole do?
Constrict to decrease blood flow and prevent overperfusion
The further you go into the glomerular capillaries, what happens to plasma colloid pressure?
*Why
It increases as you filter more fluid, so the colloids become more concentrated
Why is there no Plasma Oncotic Pressure in the Tubule/Bowman’s Capsule?
The kidney does not filter out proteins
Which vessel has the highest vascular resistance in the kidney?
The efferent arteriole
What structure fine tunes the GFR if needed?
the Efferent Arteriole
If your GFR is low, what will the efferent arteriole do?
*Value for low GFR
It will constrict to promote more filtration = increase GFR
*<125 mL/min
If your GFR is high, what will the efferent arteriole do?
*Value for high GFR
It will dilate/relax to promote less filtration
*>125 mL/min
What is the formula for Excretion?
*What is excretion
*Units
Excretion = Filtration-Reabsorption + secretion
*Removal in urine
*mL, mol, mg over time
What is Secretion?
*Which ion takes this route in excess
Physically pumping things into the tubule to get rid of
*K+
What is the Pathway for Secretion?
Peritubular Capillaries - Renal Interstitium - Cells - Tubule
What is the pathway for reabsorption
Fluid in tubule - cells on tubule wall - renal interstitium - peritubular capillaries
What is the pathway for Filtration
Glomerular Capillaries - Renal Tubules
What happens in the Peritubular Capillaries?
Lots of reabsorption
Name 2 things located within the renal interstitium
Ions/electrolytes and Proteins
Name the Pathway of Reabsorption, starting with PT
Peritubular Capillaries - Renal Vein - Systemic Circulation
What is Filtration with Partial Reabsorption?
*Which molecule follows this path
*Why
Filters and partially absorbs the molecule, then excretes the rest
*Na+ follows this; we have an increased Na+ in our diet, so the body reabsorbs what it needs and excretes the rest
What is Filtration, Complete Absorption
*Which molecule follows this route
*Why
The molecule is filtered out and completely reabsorbed
*Glucose follows this route b/c we do not have glucose in the urine
What is Filtration, Secretion
*How do we test for this
*Why do we test for this
The molecule is filtrated and all of it is secreted
*We give Paramino Hippuric Acid to the patient
*To determine a pt’s renal blood flow
The body will manipulate which structure for autoregulation of blood flow and filtration?
The Afferent Arteriole
If you have a + glucose test in urine, what could the 2 issues be?
High BSG or something wrong with the glucose transport system
If we have a decreased PAH in CL, what does that mean for renal blood flow?
Decreased renal blood flow
If we have an increased PAH in CL, what does that mean for renal blood flow?
We have increased renal blood flow
True or False: The endothelium of the glomerular capillaries is less permeable than a normal endothelium?
False; it is more permeable than normal
What are fenestrations within the renal glomerular endothelium
Specialized openings
True or False: The Epithelium provides increased support for the glomerular capillaries, as it needs to withstand high pressures
True
What is the Glomerular Capillary Basement Membrane
*What Charge does it have
Connective tissue with a (-) charge
How do Podocytes help the glomerular capillaries?
*What other group of cells are they similar to?
Help with glomerular swelling, keep surface area in check, and help glomerular capillaries from rupturing due to high renal blood pressure [>100 mmHg]
*Very similar to Astrocytes in BBB
What happens do Glomerular Capillaries with increased Renal Blood Pressure?
They rupture/fall apart
What happens with constriction of the Afferent Arteriole?
*Talk Renal Blood Flow
*Talk Glomerular Capillary Pressure
*Talk GFR
Decreased Renal Blood Flow
Decreased Glomerular Capillary Pressure
Decreased GFR
What happens with Dilation of the Afferent Arteriole?
*Talk Renal Blood Flow
*Talk Glomerular Capillary Pressure
*Talk GFR
Increased Renal Blood Flow
Increased Glomerular Capillary Pressure
Increased GFR
What happens with constriction of the Efferent Arteriole?
*Talk Renal Blood Flow
*Talk Glomerular Capillary Pressure
*Talk GFR
Decreased Renal Blood Flow
Increased Glomerular Capillary Pressure
Increased GFR
What happens with Dilation of the Efferent Arteriole?
*Talk Renal Blood Flow
*Talk Glomerular Capillary Pressure
*Talk GFR
Increased Renal Blood Flow
Decreased Glomerular Capillary Pressure
Decreased GFR
Which structure is MOST important for autoregulation of GFR and renal blood flow?
Afferent Arteriole
Which structure is MOST important for fine tuning GFR
Efferent Arteriole
If GFR is <125 mL/min, what does this mean in terms of filtration?
Less Filtration is being done
If GFR is >125 mL/min, what does this mean in terms of filtration?
More filtration is being done
What is the formula for Urine Output
GFR - Reabsorption
Which combination of size and charge would result in the least amount of filtering?
Large and (-) charged
Which combination of size and charge would result in the most amount of filtering?
Small and (+) charged
Name 5 molecules that have lower MW and are “easily” filtered
H2O, Na, Glucose, Inulin [maybe also myoglobin]
What is Inulin?
Synthetic compound that is similar to creatinine; injected to find more accurate GFR
In a Lower MAP around 50 mmHg, which is better at auto-regulating: GFR or Renal Blood Flow?
Renal Blood Flow is better autoregulating at a lower MAP
In a higher MAP around 150 mmHg, which is better at auto-regulation: GFR or Renal Blood Flow?
Both are good, but GFR AR is better
As MAP increases, what happens to Urine Output?
*Why
It increases, as your kidney tries to lower your BP by decreasing volume
As MAP decreases, what happens to Urine Output?
*Why
It decreases, as your kidney tries to raise your BP by increasing volume
If your MAP was high, and did not have any AR of GFR, what would happen to your urine output?
Urine output would be extremely high, which would be counterproductive as your body is sending blood to damaged areas, but also ridding the body of fluid at the same rate
What would you see in an increased Filtration Fraction?
*Talk Efferent Arteriole
*Talk Fluid Filtration
*Talk Colloid Osmotic Capillary Pressure
Constriction
*Increased Fluid Filtration
*Increased Colloid Osmotic Capillary Pressure
What would you see in a decreased Filtration Fraction?
*Talk Efferent Arteriole
*Talk Fluid Filtration
*Talk Colloid Osmotic Capillary Pressure
Dilation
*Decreased Fluid Filtration
*Decreased Colloid Osmotic Capillary Pressure