Tissue Fluid Flashcards
What is the blood flow equation
What is poiselles law
Change in pressure / resistance
Flow = pie r cubed x change in pressure / (8 x viscosity x length)
What will longer vessels have and what does this mean
What do medications affect
What is the biggest effector of flow
A large surface area and a greater resistance.
Blood viscosity. Taking erythropoietin increases rbc count and gives thicker blood.
Pie x radius because a very small radius decrease will cause a massive flow decrease.
What part of the capillary has the highest resistance and why
What is another name for this place
Where is the best place to treat high bp
The arterioles have the highest resistance because the radius has decreased when it splits off from the artery. They are called resistance vessels.
The arterioles are a key place where blood pressure can be treated due to their high resistance.
Why can vessels collapse
What is the law of Laplace
They are elastic and not rigid.
This pressure from the surrounding tissue can collapse vessels is the blood pressure becomes too low.
For open vessels:
Transmural pressure = tension/ radius
Tension = p x r / wall width.
Aneurysm
Ballooning of the vessel due to a weak point in the vessel wall.
The smaller it is the greater pressure on the vessel wall.
The bigger it gets the thinner the wall gets and the more likely it is to burst.
What is compliance
Are veins or arteries more compliant
Vessel walls have a certain degree of give.
Compliance = change in volume times pressure
Veins are more compliant than arteries and store more blood and they are called capacitance vessels.
Which vessels are elastic
How does this help blood flow
Arteries and veins
When the left ventricle is in systole the vessels will stretch due to blood and during diastole the vessels will recoil.
This results in pulsatile continuous flow due to the continuous stretch and recoil. Windkessel effect.
In a rigid tube this would not happen.
Laminar and turbulent blood flow
Which flow is in alveolar vessels
In laminar flow the blood will travel in a straight line down the tube.
Turbulent is irregular with tiny whirlpool regions and hitting walls.
Turbulent because the rbcs are tumbling around and hitting the walls and this is needed for gas exchange.
What is bad about laminar flow
Why don’t cell live long
It can produce blood clots because of how orderly the blood will flow and won’t be mixed.
The blood cells don’t have a long lifespan due to all the turbulence.
What is the mean arteriolar pressure
Why does blood velocity decrease in arterioles
Where is the greatest amount of blood volume stored.
35mmHg
High resistance
Venous system
How much of the body’s blood is in capillaries
What is velocity like in capillaries
What are inactive capillaries
5%
Low it takes 2/3 seconds to pass through a whole capillary.
Inactive capillaries have their sphincters closed so no blood can enter
Pre capillary sphincters direct blood flow to or away from capillaries
Tissue fluid formation
Plasma in blood can leave capillaries and go into surrounding tissues and become interstitial fluid.
Filtration through cells is transcellular and between cells is paracellular.
The net fluid transfer forms tissue fluid.
Tissue fluid formation depends on
The hydrostatic pressure difference between the capillary and interstitial fluid.
The difference in colloid osmotic pressure. The more proteins in the blood the greater the pressure and the less fluid that will leak out of capillaries.
The balance between the two pressures determines the net tissue fluid.
High blood pressure causes more tissue fluid production
What is the capillary filtration coefficient
The ease of flow across the vessel wall. Depends on the size and frequency of holes in capillaries.
How is tissue fluid removed
By lymph
