Any of the tubular branching vessels that carry blood from the capillaries toward the heart.
hog:0001250
hog:0000014
extraembryonic vitelline veinhog:0000015
extraembryonic umbilical veinhog:0000642
hepatic portal veinhog:0001133
pulmonary veinhog:0001194
posterior vena cavahog:0001195
anterior vena cavahog:0001197
cardinal veinhog:0001216
venous system endothelium
BFO:0000050
part of
hog:0000277
tao:0000082