connects venule arteriole blood vessel capillary AAO:0010252 Any of the smallest blood vessels connecting arterioles with venules. Any of the tiny blood vessels connecting the arterioles to the venules.[AAO] BTO:0002045 CALOHA:TS-2006 EFO:0001906 EMAPA:35198 EV:0100035 FMA:63194 MA:0000065 MESH:A07.231.432.410 OpenCyc:Mx4rvWEU-5wpEbGdrcN5Y29ycA TAO:0005250 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] UBERON:0001982 UMLS:C0935624 VHOG:0001253 XAO:0000116 ZFA:0005250 blood capillary capillaries lack tunica media and tunica adventitia; only the endothelial wall of the tunica intima belongs capillary vessel not all sources agree capillary is a blood vessel - consider adopting EMAPA superclass of vascular element uberon microcirculatory vessel