n
A system of interconnected blood vessels that returns blood to the heart from the tissue and capillary bed through progressively larger vessels. The following affect the return of blood to the heart: thoracic pressure, associated with respiration; gravity, associated with body posture; the valves, diameter of the lumen, and muscle structure of the veins; muscle contraction of the somatic structures; the pressures in the arteriole system and capillary bed; and the nervous and hormonal system controls that regulate cardiomuscular activity. The influences over the venous system circulation are collectively termed venopressor mechanisms.
