Now, from our right atrium, our blood flows through this valve system and into the right ventricle. So number two, it then enters the right ventricle. And this is essentially where the systemic circulation ends and the pulmonary circulation begins. So remember, pulmonary circulation means we take the deoxygenated blood, we bring it to our lungs where we oxygenate that blood and then we bring the oxygenated blood back to our heart. So number two is where the pulmonary circulation begins. So the right ventricle basically pumps the de oxygenated blood into this artery that diverges into the left pulmonary artery.