anatomy
vein
also: veins
one of the numerous BLOOD VESSELS carrying deoxygenated blood to the right ATRIUM of the HEART (the one exception is the PULMONARY vein). Each vein has three tissue layers, similar to the layers of the heart. Veins are less elastic than arteries and collapse when cut. They also contain VALVES to prevent back flow.
Source: mediLexicon corpus · slug
vein