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).
NOTE The function of veins is to return blood to the heart. Veins have thinner walls and have one way valves in them. 1  those that take blood from the heart to the lungs to be re-oxygenated; known as the pulmonary arteries. 2  These are the only arteries that transport de-oxygenated blood.