Pulmonary circulation where carbon dioxide is released and oxygen is picked up during respiration. Arteries are further divided into very fine capillaries which are extremely thin-walled. The pulmonary vein returns oxygenated blood to the left atrium of the heart. The oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. This blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. From the left ventricle, the blood passes through the aortic valve to the aorta. The blood is then distributed to the body through the
Blood-vein "Atriplex". It overwinters as a larva. 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.