A person stands up. Compared with the recumbent position, 1 minute after standing, the
Skin blood flow increases
Volume of blood in leg veins increases
Cardiac preload increases
Cardiac contractility decreases
Standing up increases the transmural pressure in the veins of the legs. Because the veins are highly compliant, their volume increases at the expense of central blood volume.A lower central blood volume means reduced cardiac filling pressure (preload). Within seconds, the decrease in preload decreases stroke volume, cardiac output, and aerial pressure.
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