WASHINGTON, DC - JANUARY 20: U.S. President Donald Trump delivers his inaugural address on the West Front of the U.S. Capitol on January 20, 2017 in Washington, DC. In today's inauguration ceremony Donald J. Trump becomes the 45th president of the United States.
One-Way Valves in the Veins. One-way valves consist of two flaps (cusps or leaflets) with edges that meet. These valves help veins return blood to the heart. As blood moves toward the heart, it pushes the cusps open like a pair of one-way swinging doors (shown on the left).
valves are only present in veins to stop the blood to move backwards through the vein but in arteries the muscle puts alot of pressure on the blood which stops it from moving in the wrong direction.rteries do not need them as the blood in them is being pumped out from the heart under pressure. The pressure it â¦ self prevents backflow. It is interesting to note that veins in the head and upper chest don't have valves either, because blood in them flows under gravity.