Blood air to all of the cells of the body, and venous blood carries carbon dioxide, a waste product of metabolism by cells, to the lungs to be exhaled. However, one exception includes pulmonary arteries, which contain the most deoxygenated blood in the body, while the pulmonary veins contain oxygenated blood. Additional return flow may be generated by the movement of skeletal muscles, which can compress veins and push blood through the valves in veins toward the right atrium. The blood circulation was famously described by William Harvey in 1628. In vertebrates, the various cells of blood are made in the
Renal vein Renal vein The renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava. They carry the blood filtered by the kidney. There is one vein per kidney, that divides into 4 divisions upon entering the kidney: Because the inferior vena cava is on the right half of the body, the left renal vein is generally the longer of the two. Because the inferior vena cava is not laterally symmetrical, the left renal vein often receives the following veins: This is in contrast to the right side of the body, where these veins drain