Vitelline veins the developing liver and broken up by it into a plexus of small capillary-like vessels termed sinusoids. The vitelline veins give rise to Inferior mesenteric vein, Ciliac trunk The branches conveying the blood to the plexus are named the venae advehentes, and become the branches of the portal vein. The vessels draining the plexus into the sinus venosus are termed the venae revehentes, and form the future hepatic veins. Ultimately the left vena revehens no longer communicates directly with the sinus venosus, but opens into the right vena revehens. The persistent part of the upper venous ring, above the opening
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