Lecture 12: Venous Blood Flow and the Heart Flashcards
Where is most of the blood in our body found?
Systemic veins
Why can’t we store extra blood in our pulmonary circuit?
It is too small
Why can’t we store extra blood in our systemic arteries?
It would raise our blood pressure
Why can’t we store extra blood in our capillaries?
They are too small
How are veins able to store more blood in them?
They have a higher compliance
What allows veins to have a higher compliance?
They have a thin tunica media which allows room for compliance
What doesn’t allow arteries to have a higher compliance?
Thick tunica media forming a more rigid structure
What is compliance?
The extent to which a vessel allows deformation in response to an applied force
What is the equation for compliance?
Delta V/P
What does it mean for compliance if it takes more pressure to change the volume of a vessel?
The less compliant it is
What allows arteries to maintain their shape even under low pressure?
A thick tunica media
What happens to veins under low pressure?
They collapse as pressure conforms shape
What does a small portion of pressure do to the volume of a vein?
It causes a large change in volume
What is meant by veins having survival value?
They can move blood over to arteries in an emergency situation
What is venoconstriction?
contraction of veins pushing blood stored there into the arteries
