starting with the heart, blood is pumped into the right atria to the right ventricle. this then goes to the pulmonary artery to the lungs where it is oxygenated. from here, the blood goes through the pulmonary veins back to the heart via the left atria and left ventricle. the left ventricle leads tot he aorta and the rest of the body. the blood returns to the heart via the vena cava to the right atrium