[The effect of gravity on linear blood flow velocity in different parts of the venous system in humans].
Effects of gravity on linear blood velocity in jugular, femoral and popliteal veins were examined in 45 healthy male and female subjects. The zero-g effects were simulated by putting the subjects in the recumbent position, and the gravity effects were provoked by active orthostasis. Blood velocity was measured with CW Doppler (4 MHz). No difference was determined in velocity of the blood flow along the veins in recumbent subjects. In the head-up position, blood flow was significantly increased in the jugular vein and decreased in the leg veins. In several instances, brief contraction of the crus muscles caused a noticeable rise in the peak velocity along the femoral vein. In the head-up position this hemodynamic effect of the crus pump was much more pronounced.
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D001783:Blood Flow Velocity / Q000502:physiology*; D006112:Gravitation; D006801:Humans; D014680:Veins / Q000502:physiology*