Vein cells called tunica intima. The precise location of veins varies much more from person to person than that of arteries. Veins serve to return blood from organs to the heart. Veins are also called "capacitance vessels" because most of the blood volume (60%) is contained within veins. In systemic circulation oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where its nutrients and gases are exchanged at capillaries. After taking up cellular waste and carbon dioxide in capillaries, blood is channeled through vessels that converge with one another to form
Trabecular veins Trabecular veins The trabecular veins are the largest veins inside the spleen. It drains the blood collected in the sinuses of the pulp. The blood is collected from the interstices of the tissue by the rootlets of the veins, which begin much in the same way as the arteries end. The connective-tissue corpuscles of the pulp arrange themselves in rows, in such a way as to form an elongated space or sinus. They become elongated and spindle-shaped, and overlap each other at their extremities, and thus form a sort of endothelial lining of the path or sinus, which is the