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
Blood-vein Blood-vein The blood-vein, ("Timandra comae") is a moth of the family Geometridae. It has a scattered distribution in western and central Europe north of the Alps. In the British Isles the distribution is patchy outside southern England and Wales. In far eastern Europe – east of a line running roughly from Finland through Estonia –, it is replaced by its sister species "Timandra griseata". The species were split in 1931, only to be subsequently re-merged by most authors. But since 1994, new research has come out in favour of treating them as distinct species. The wings are cream coloured with