Physiology-Venous System Function

Question 1

Where do we reference all pressures to in the cardiovascular system?

Answer 1

Phlebostatic axis

Question 2

What function illustrates the blood storage component of the cardiovascular system?

Answer 2

Compliance

Question 3

How can you modulate the venous system when someone is hemorrhaging to help save their life?

Answer 3

Stimulate the sympathetic nervous system to contract the vessels. This will decrease venous storage and decrease compliance, pushing more blood into the arterial system for perfusion of tissue.

Question 4

What makes the venous system more compliant?

Answer 4

Increasing pressure via intravenous infusion.

Question 5

What happens to venous return if you had a tumor growing in the right atrium? At what point would the tumor cause the heart to stop.

Answer 5

It decreases. Once the right atrium is clogged to the point that venous return = 0, you have reached the mean systemic filling pressure. At this point the heart would stop.

Question 6

Why doesn’t venous return increase linearly as right atrial pressure decreases?

Answer 6

There is a certain negative pressure at which veins will collapse.

Question 7

How does the venous return keep up with an increasing cardiac output?

Answer 7

You could infuse fluids to increase venous return to the heart. Decrease resistance to venous return. You could also squeeze with your muscles. This can increase cardiac output from 5L/min to 20L/min.