Venous Return Flashcards
Venous return refers to the amount of blood and blood flow
returned back to the heart from veins
Therefore, since CO is 5 L/min, venous return
also equals 5 L/min.
Arthur Guyton correlated the relationship between 2 things to control venous return.
mean systemic filling pressure (MSFP) and right atrial pressure (RAP)
MSFP is approx
RAP is approx
CO is appr
7 mm Hg
0 mmHg
5L/min
As CO (or venous return) increases, CVP
Decreases and more blood is pumped from veins to the right atrium.
Consequently, increases in MSFP or decreases in RAP lead to
increased venous return
Venous return increases as the pressure difference
between
RAP and MSFP increases.
If RAP (or CVP) is low and MSFP high, then there will be a
maximum change in
pressure and a maximum venous return of blood to the right
heart.
On the other hand, if RAP increases, but there is no
change in MSFP, then there will be a small difference between the two variables and venous return will
decrease
Anything that causes volume retention
increases MSFP.
Alternatively, situations that decrease blood volume, such as hemorrhage and dehydration,
decrease MSFP and venous return.
Peripheral veins have _____ valves that.
one-way direct flow of blood away from the limbs and toward the heart
Muscle contraction causes venous_________, and muscle relaxation causes venous ______
compression;decompression.
The alternative contraction and relaxation patterns cause blood to be pumped
back to the heart, and unidirectional valves prevent blood from flowing back toward the limbs, enhancing venous return
Respiratory activity influences venous return to the heart by
augmenting the pressure difference between abdominal veins and the right atrium.
