Human Circulation
This consists of two closed circuits: the systemic circulation and the pulmonary circulation. The
left heart pumps blood around the systemic circulation, receiving oxygen-rich blood from the lungs and
pumping it out to the rest of the body (so this blood is red). The right heart pumps blood around the
pulmonary circulation, receiving de-oxygenated (blue) blood from the body, and pumping it to the lungs.
Heart Blood Vessels
The top of the heart is connected to several large blood vessels. The largest of these is the aorta which carries nutrient-rich, oxygenated blood away from the heart. The pulmonary trunk connects the heart to the left and right pulmonary arteries which take oxygen-depleted blood from the heart to the lungs. The two large veins that carry blood back into the heart are the superior vena cava and the inferior vena cava.
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