circulatory system: human

The human circulatory system consists of a pulmonary system and a systemic system. In the pulmonary system blood is carried from the heart to the lungs then back to the heart. It starts off by deoxygenated blood flowing through the right atrium via the vena cava, to the right ventricle. Blood is then pumped from the pulmonary artery to the lungs, where an exchange of blood occurs. Then the oxygenated blood flows through the left atrium beginning the systemic system. In the systemic system oxygenated blood flows from the heart to the body then back to the heart. First the oxygenated blood from the lungs flows through the left atrium then to the left ventricle. Then from the left ventricle it then flows through the aorta, where it then goes to all parts of the body. This is where an exchange of gases happens in the tissue. Finally, deoxygenated blood flows through the vena cava to the right atrium, where the circulatory system repeats itself.