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36 Cards in this Set
- Front
- Back
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What are the two different capillary beds? |
glomerular and peritubular |
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What type of capillaries have the highest rate of filtration? Is there reabsorbtion here? |
Glomerular capillaries No |
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What is the main force that drives filtration in the glomerular capillary? |
hydrostatic pressure |
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What happens to oncotic pressure as it passes through the glomerular capillaries? |
It gets higher |
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What is the oncotic pressure in the bowman's capsule? What's going on if there is an increase in the oncotic pressure? |
0 It means that the permeability of protein in the glomerular capillary has increased and this is pathologic |
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What is NFP? |
Net filtration pressure It is calculated in mm Hg [Glomerular capillary(GC) hydrostatic pressure - GC osmotic pressure] - Bowman's capsule hydrostatic pressure Forces moving out - forces keeping fluid from moving out |
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What is the filtration coefficient(Kf)? |
Hydraulic permeability x Surface area |
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What happens when you have renal disease? |
lose nephrons and tubules, which decreases your surface area. |
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If your afferent arteriole dilates, what can you expect to happen? |
Glomerular capillary hydrostatic pressure can increase, then due to the pressure the surface area will increase. |
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If your afferent arteriole constricts, what can you expect to happen? |
Glomerular capillary hydrostatic pressure can decrease, then due to the drop in pressure the surface area will decrease. |
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What does an increase in surface area mean for filtration coefficient? What about for GRF? |
It means that it will go up That will go up, too |
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What happens for patients with liver problems? |
There is less protein, so a drop in oncotic pressure, which will increase filtration because the lack of proteins will not be able to hold onto the fluid. |
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What can increase the bowman's capsule pressure? |
kidney stone/obstruction/UTI |
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If we constrict anything along the blood flow system, what will happen to renal blood flow? |
It will drop |
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If we do anything medication wise for constriction or dilation where are we thinking that it occurs? What's the exception to this? What does it affect instead? |
Afferent arteriole Renin-aldosterone will effect the efferent arterioles. |
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What does adding oncotic GC pressure and pressure in the glomerular capillaries do? |
It shows you the total opposing force of filtration |
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Do all the processes really just effect the afferent or efferent arterioles? |
No, they really actually effect both, they just effect one more than the other. |
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Does hydrostatic pressure change much throughout the glomerular capillaries? |
Nope, like 2 mm Hg |
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What is the hydrostatic pressure in the peritubular capillaries? What does this do in relation to reabsorption? |
20 mm Hg It opposes |
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What is the oncotic pressure in the peritubular capillaries? What does this do in relation to reabsorption? Where is this oncotic pressure similair to? |
36 mm Hg It helps in reabsorption It is similar to the oncotic pressure in the efferent arterioles |
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What is the interstitial hydrostatic pressure? What does this do in relation to reabsorption? |
3 mm Hg It favors reabsorption |
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What is the interstitial oncotic pressure? What does this do in relation to reabsorption? |
6 mm Hg, there is a decent # of proteins that get stuck in the renal interstitium. It opposes reabsorption |
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Where are most of the peritubular capillaries and how much? Where are the rest? What are they called? |
90-95% are in the out medulla/cortex 5-10% are in the deeper parts of the kidney and called the vasorecta(VR) |
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How many parts are there to the vaso recta? What are they called? |
2 Ascending vasorecta and descending vasorecta |
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What happens in the ascending vaso recta? |
It divides, so the blood passes through it more slowly. This occurs, so there is not much reabsorption that occurs and it can allow for more wastes to be secreted. It eliminates washout. |
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So, looking back that the pt with liver failure, what happens in the kidney? |
Decrease in # of proteins, this means less "stuff" to hold onto the fluid, so more gets filtered out, but when you get to the peritubular capillaries, there's still not much protein because the liver can't make any because it's failing, so there also isn't much pull back into the blood. -This is decreased reabsorption. |
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What is the cardiac output? How much goes through the kidneys? How much is RBC? Plasma? So what is the proportion of what if filtered off the plasma? What percent? |
5 liters/min 1100 mL/min 440 ml/min 660 mL/min 125 mL / 660 mL of plasma: Approximately 20% |
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What is clearance? |
how much volume of plasma is cleared of a substance per unit of time |
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What does it mean for a substance to be cleared? |
It has to be removed from plasma and placed into the urine unchanged. |
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What are the typical units for clearance? |
mL/min |
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Where is creatinine made? What is the normal concentration in the blood? |
In the muscle 1 mg/dL |
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How much water is reabsorbed? How much salt is reabsorbed? |
99% 98% |
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Where is there the same concentration of creatinine? |
Glomerular capillaries, efferent arteriole, and bowman's capsule |
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Is creatinine reabsorbed? |
Nope, it stays in the tubule |
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What is urine production? |
1 mL/min |
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How do we calculate clearance? |
(Vx x Ux)/Px x-substance P - blood concentration V - urine flow U - urine concentration |
