There are four pulmonary veins that return oxygenated blood from the lungs to the left side of the heart. After blood enters the heart it is pumped to the rest of the body through the aorta. The blood returns to the heart through the vena cava and is then pumped back to the lungs through the pulmonary artery.
Figure 1: Location of the heart and lungs in the body.
Figure 2: Pulmonary arteries and veins.
Figure 3: Side view of the pulmonary veins.
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