channel for vein AAO:0010212 AEO:0000209 Any of the tubular branching vessels that carry blood from the capillaries toward the heart. BTO:0000234 CALOHA:TS-1108 EFO:0000816 EHDAA2:0003254 EMAPA:35906 EV:0100031 FMA:50723 GAID:492 MA:0000067 MAT:0000037 MESH:D014680 MIAA:0000037 OpenCyc:Mx4rvVjkWpwpEbGdrcN5Y29ycA Part of the circulatory system composed of blood vessels which carry blood from other organs, tissues, and cells to the heart.[AAO] TAO:0000082 TODO - check with MA - vein vs venous blood vessel The appearance of Chordata and subsequently the vertebrates is accompanied by a rapid structural diversification of this primitive linear heart: looping, unidirectional circulation, an enclosed vasculature, and the conduction system.[well established][VHOG] UMLS:C0042449 VHOG:0001743 XAO:0000115 ZFA:0000082 galen:Vein vascular element vena venae venous subtree venous tree organ part venous vessel venous blood vessel venous blood