Red blood cell synthesised by the kidney. Just before and after leaving the bone marrow, the developing cells are known as reticulocytes; these constitute about 1% of circulating red blood cells. The functional lifetime of a red blood cell is about 100–120 days, during which time the red blood cells are continually moved by the blood flow push (in arteries), pull (in veins) and a combination of the two as they squeeze through microvessels such as capillaries. They are also recycled in the bone marrow. The aging red blood cell undergoes changes in its plasma membrane, making it susceptible to selective recognition by
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