How does the blood pumped from the heart to the rest of the body and back again?

The heart sends deoxygenated blood to the lungs, via the pulmonary arteries - thus this system is called the pulmonary circuit

De-oxygenated blood flows from right ventricle of heart to lungs through two pulmonary arteries for oxygenation. After oxygenation the blood now travels through the pulmonary veins to left auricle of heart. Two pulmonary veins from each lung reach the heart making a total of four pulmonary veins. This circulation of blood to and from lungs is called pulmonary circulation. The pulmonary vein is thus the only vein which carries oxygenated blood and pulmonary artery in the same way the only artery to carry deoxygenated blood.