Systemic circulation moves blood between the heart and the rest of the body. It sends oxygenated blood out to cells and returns deoxygenated blood to the heart. Systemic heart refers to the left auricle and left ventricle in higher vertebrates. In Pulmonary circulation, deoxygenated blood pumped into the pulmonary artery is transferred to the lungs from where the oxygenated blood is carried by the pulmonary veins into the left atrium. Related Theory Systemic circulation is ordered from the left ventricle to the aorta, through the structures of the body, to the superior or inferior vena cava, and re-enters the heart in the right atrium. The pulmonary circulation is a relatively low pressure system compared to the systemic circulation because the pulmonary arteries are not as muscularized as their systemic counterparts.