Blood is pumped out of our body but pressure; which is what we call a "blood pressure".
Blood will enter our heart from after being circulated through the body to re-oxygenate through the superior and inferior vena cava and dumps the floor into the right atrium. Blood passes through the tricuspid valve and enters the right ventricle. From the right ventricle it passes into the pulmonary valve.
From the pulmonary valve is goes through the pulmonary artery (which is the only artery to carry deoxygenated blood) and goes into the lungs for diffusion (oxygen/carbon dioxide exchange) to re-oxygenate the blood and get rid of the carbon dioxide from the blood and out through the lungs.
After the blood passed through the capillaries via the lungs; it goes through the pulmonary vein (the only vein to carry oxygenated blood) and returns back into the heart at the left atrium.
Blood will pass from the left atrium through the bicuspid valve (mitral valve) and into the left ventricle. After the left ventricle, the blood is ready to circulate into the body and will pump out through the aorta.
