Vein venules, which continue to converge and form the larger veins. The de-oxygenated blood is taken by veins to the right atrium of the heart, which transfers the blood to the right ventricle, where it is then pumped through the pulmonary arteries to the lungs. In pulmonary circulation the pulmonary veins return oxygenated blood from the lungs to the left atrium, which empties into the left ventricle, completing the cycle of blood circulation. The return of blood to the heart is assisted by the action of the muscle pump, and by the thoracic pump action of breathing during respiration. Standing or
Renal vein thrombosis renal function or renal failure. These symptoms may vary in duration since a blood clot can resolve itself, but precautions should be taken to prevent the migration of the clot to other parts of the body. The most severe complication of RVT is a pulmonary embolism, caused by a clot, also called a thrombus, that originates from the renal vein or any other vein in the body and migrates to the pulmonary artery. A pulmonary embolism is a serious condition because; it can damage the lungs due to pulmonary hypertension and cause low blood oxygen, damaging other organs in the