Topic summary
Venous valves
Extracted from the Wikipedia article Vein.
Venous valves
Blood flows back to the heart in the systemic deep veins, with the flow of blood maintained by one-way valves in the deep veins, superficial veins, and in the perforator veins. The venous valves serve to prevent regurgitation (backflow) due to the low pressure of veins, and the pull of gravity. They also serve to prevent the over-widening of the vein.