24.13
Venous return refers to the volume of blood flowing back to the heart through systemic veins.
It is primarily driven by the pressure difference between the venules and the right ventricle.
In addition, the skeletal muscle pump and the respiratory pumps also assist in venous return.
In the skeletal muscle pump, contraction of the leg muscles while standing on the toes causes the proximal venous valve to open, pushing blood upward, an action called milking. After the muscles relax, the distal venous valve opens up to push blood upward. Such a sequential contraction and relaxation of muscles help regulate the venous return.
The respiratory pump works based on alternating compression and decompression of veins during inhalation and exhalation.
When the diaphragm moves downward during inhalation, pressure decreases in the thoracic cavity and increases in the abdominal cavity, leading to vein compression and a greater volume of blood moving to the heart.
The circulatory system plays a crucial role in ensuring the optimal functioning of the human body. One of its critical components is venous return - t…
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