Suprachoroid lamina which the vessels and nerves are transmitted. Suprachoroid lamina The choroid consists mainly of a dense capillary plexus, and of small arteries and veins carrying blood to and returning it from this plexus. On its external surface is a thin membrane, the suprachoroid lamina, composed of delicate non-vascular lamellae—each lamella consisting of a network of fine elastic fibers among which are branched pigment cells. During embryological development, it is derived from the neural crest. The spaces between the lamellæ are lined by endothelium, and open freely into the perichoroidal lymph space, which, in its turn, communicates with the periscleral space
Blood air to all of the cells of the body, and venous blood carries carbon dioxide, a waste product of metabolism by cells, to the lungs to be exhaled. However, one exception includes pulmonary arteries, which contain the most deoxygenated blood in the body, while the pulmonary veins contain oxygenated blood. Additional return flow may be generated by the movement of skeletal muscles, which can compress veins and push blood through the valves in veins toward the right atrium. The blood circulation was famously described by William Harvey in 1628. In vertebrates, the various cells of blood are made in the