part_of part of embryonic structure post-anal tail bud Kupffer's vesicle ZFA:0000001 uberon Small but distinctive epithelial sac containing fluid, located midventrally posterior to the yolk cell or its extension, and transiently present during most of the segmentation period. Kimmel et al, 1995. Kupffer's vesicle has been compared to the mouse embryonic node. Drummond et al, 2005. UBERON:2000001