The document lists and describes the major systemic veins in the human body that return deoxygenated blood from the tissues back to the heart. It includes the superior and inferior vena cava, which are the two major veins that drain into the right atrium of the heart, as well as several other important veins like the brachiocephalic, subclavian, jugular, iliac, femoral and saphenous veins. The document also notes that veins have a similar structure to arteries but contain valves to prevent backflow of blood.