What documents do I need to present to reenter the United States? If seeking to enter the United States after temporary travel abroad, you will need to present a valid, unexpired âgreen cardâ (Form I-551, Permanent Resident Card).
Brain Tour. 2. Supply lines. Your brain is nourished by one of your body's richest networks of blood vessels. With each heartbeat, arteries carry about 20 to 25 percent of your blood to your brain, where billions of cells use about 20 percent of the oxygen and fuel your blood carries. When you are thinking hard, your brain may use up to 50 percent of the fuel and oxygen.
An artery is an elastic blood vessel that transports blood away from the heart. There are two main types of arteries: pulmonary arteries and systemic arteries.Pulmonary arteries carry blood from the heart to the lungs where the blood picks up oxygen.The oxygen rich blood is then returned to the heart via the pulmonary veins.Systemic arteries deliver blood to the rest of the body.here are two main types of arteries: pulmonary arteries and systemic arteries. Pulmonary arteries carry blood from the heart to the lungs where the blood picks up oxygen. The oxygen rich blood is then returned to the heart via the pulmonary veins. Systemic arteries deliver blood to the rest of the body.