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33 Cards in this Set
- Front
- Back
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What are starling forces in the kidneys? |
this governs what is going on in the capillary beds. |
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What is hydrostatic pressure? |
It is the force exerted by the fluid. It's like blood pressure. |
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What happens to blood pressure as we get further away from the heart? What causes this? |
It drops. 1) There is a lot more pathways that pop up, so the increase in surface area, decreases the pressure. 2) The increase in pathways causes there to be a lot more vascular resistance forcing the pressure down. |
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What is the pressure in the aorta and the larger arteries? |
It is around 100 mm Hg |
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Which part of the cardiovascular system has the highest vascular resistance? What does this mean for the BP? |
The arteriole have the largest vascular resistance. This cause there to be the highest drop in BP. |
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What do arterioles do in terms of blood flow to the capillaries? |
It controls how much goes through the capillaries. |
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What happens at the capillary bed? |
Nutrient and waste exchange. At the arteriolar end of the capillary you want a higher BP of about 30 mm Hg, then at the venular end of the capillary you want a lower BP of about 10 mm Hg. This will help the blood to be driven from one side to the other side. |
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What is the delta P? What happens when the delta P changes? |
It is the change in pressure from the arteriolar end to the venular end. Increased change means increased blood flow and perfusion to the tissues. |
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What happens downstream if the arteriolar relaxed or constricted? |
Relaxation will have an increased pressure because there is less vascualr resistance. Constriction will cause the pressure to decrease because of increased vascular resistance. |
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So hydrostatic pressure in blood vessels is caused by what? |
The heart |
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What is the interstial pressure? How is it created? |
It's the fluid in the container outside of our blood vessels. It is typically a negative pressure to promote a fluid shift out. It is caused by our lymphatic system, which work like our vessels. It works like a vacuum and when our muscles squeeze on the lymphatics, so it pinches to promote a one way direction of fluid. |
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What is colloid osmoticpressure? |
It is the proteins in the space. It maintains the same throughout, since there is no real change in number of proteins in the blood vessel. Proteins don't usually shift out into the interstitium. The typical pressure is 28 mm Hg. |
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What are the two measures of colloid osmotic pressure in a normal capillary? |
Plasma osmotic pressure - 28 mm Hg Interstial osmotic pressure - 8 mm Hg |
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So what is our filtration rate at the arteriolar end of the normal capillary? |
13 mm Hg out |
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So what is our reabsorption rate at the venular end of the normal capillary? |
7 mm Hg in |
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How much fluid does the lymphatic system handle? |
a few hundred ccs per day |
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That's kinda high... what makes this number more managable for the lymphatic system? |
Tons of difficult math, but overall the average capillary pressure is 17.3 and at the end of the day the total outward force is 28.3 and the total inward force is 28. This means the lymphatic system really handles about 0.3. |
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If the heart can't pump fluids forward, what happens to the venular hydrostatic pressure? |
it increases because the fluid is backing up. |
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Where is there little vascular resistance between the renal arteries and the glomerular capillaries? |
Segmental, interlobar, and arcuate ateries don't have much vascular resistance |
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So, where does the vast majority of vascular resistance come from? |
the afferent arterioles |
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What is the hydrostatic pressure at the arteriolar end of the glomerular capillaries? |
60 mm Hg |
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What it the osmotic pressure in the glomerular capillaries? |
28 in the beginning, 32 middle, and 36 in the end. |
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What is the bowman's capsule pressure? |
18 mm Hg It comes from the force of the bulk of fluids moving out of the glomerular capillaries and into the bowman's capsule. This is the 1st part of the tubule. |
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If there is an increase in pressure at the glomerular capillary what could be happening between the heart and the kidneys? |
There could be a decrease in the vascular resistance between the two! |
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What gets filtered out at the glomerular capillaries? |
water, ions, gases, and small waste products |
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What stays in during filtration? What does that contribute to? |
Proteins This is what contributes to oncotic pressure |
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So what happens to oncotic pressure along the length of glomerular capillaries? |
It increases as fluids get filtered out because the proteins can't get filtered out. |
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What functional purpose do podocytes do for the glomerular capillaries? |
They help to counteract the high pressures in the capillaries. |
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What is filtration fraction? |
How much fluid is getting filtered out. |
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What happens to the filtration fraction as we move along the glomerular capillary? |
It decreases. |
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If there is a higher filtration fraction what happens to the colliod concentration? |
it also increases. |
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If BP drops and there is increased colloid concentration, what will happen at the peritubular capillaries? |
There will be increased water reabsorbtion. |
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What happens when you squeeze and dilate the efferent arteriole? |
Dilate: drop hydrostatic pressure Squeeze: increase hydrostatic pressure |
