Peripheral Vasculature Flashcards
(37 cards)
What happens to blood flow after you eat a big meal?
It is shunted to the GI system.
Are capillaries different in each system?
YES. They are different in the liver, skin, brain, and muscle. (ex. capillaries are tight in the brain (BBB) and testes (BTB), but leaky in the kidney).
How do the pulmonary and systemic circuits compare in terms of pressure?
The systemic circuit is higher in pressure than the pulmonary circuit.
Should we think about the arteries as a separate organ system?
YES
Should we think about the veins as a separate organ system?
YES, they are very compliant.
Should we think about capillaries as their own system?
YES
Why shouldn’t you jump in the pool after eating a big meal?
because the blood in your body is shunted to your GI tract and when you recruit the muscles you need for swimming, there is less blood flow and therefore less O2 being delivered to them, making cramps much more likely.
What happens to blood flow when you work out and start to overheat?
the blood flow gets dissipated to the extremities to release heat.
Does the arterial or venous system have higher O2 tension?
arterial
In what system does high BP occur?
the arterial system (not the venous system)
Is the arterial or venous system more compliant?
venous system
**What is the most important characteristic of the aorta?
it is elastic and acts as a secondary pump!
Where is the greatest cross sectional area?
capillaries because there are billions of them
**What is the most important characteristic of the vena cava?
it is compliant (can hold large volumes at LOW pressure)
Is elasticity the inverse of compliance?
YES
What happens to the amount of smooth muscle as we move toward the precapillary sphincter?
it increases. This is good, because if you are in shock due to a major car accident and have internal bleeding, you need blood flow to be shunted toward the internal organs, so the precapillay sphincters of the skin will constrict, reducing blood flow to the skin where it isn’t needed.
Do the capillaries have smooth muscle?
NO. they are very thin and only have a single layer of endothelium.
Where is blood volume greatest?
in the venous compartment
What is the hematocrit?
% of RBCs per unit volume. The hemoglobin is what makes up this hematocrit.
Where is the greatest pressure in the vasculature at any one time?
In the aorta.
Where is the largest pressure drop at any one time?
at the level of the arterioles
Is there still pressure at the level of the capillaries?
YES because you need some pressure for filtration
Where is velocity the greatest and lowest, respectively?
velocity is greatest in the aorta, and lowest in the capillaries.
What is the velocity of blood in the vena cava (relative to the velocity of the aorta)?
about 2/3 that of aortic velocity (so it picks back up after the capillaries). biphasic looking curve (looks like a water glass)
