contains process contains process develops_from develops from has potential to develop into has potential to develop into angiogenesis hemopoiesis hematopoietic system blood island posterior blood island TAO:0000094 relationship loss: part_of intermediate cell mass of mesoderm (TAO:0000033)[TAO] AAO:0011006 caudal hematopoietic tissue EHDAA:207 Small clusters of mesodermal cells called blood islands mark the embryonic debut of the cardiovascular system (in vertebrates) (reference 1); In birds and mammals, primitive hemangioblasts are extraembryonic, populating the yolk sac as the so-called blood islands (reference 2).[well established][VHOG] NCIT:C34113 ventral blood island EHDAA2 distinguishes 3 types, but does not have a superclass. The VHOG class may refer to yolk sac Blood islands are structures in the developing embryo which lead to many different parts of the circulatory system. They primarily derive from plexuses formed from angioblasts. Within them, vacuoles appear through liquefaction of the central part of the syncytium into plasma. The lumen of the blood vessels thus formed is probably intracellular. The flattened cells at the periphery form the endothelium. The nucleated red blood corpuscles develop either from small masses of the original angioblast left attached to the inner wall of the lumen or directly from the flat endothelial cells. In either case the syncytial mass thus formed projects from and is attached to the wall of the vessel. Such a mass is known as a blood island and hemoglobin gradually accumulates within it. Later the cells on the surface round up, giving the mass a mulberry-like appearance. Then the red blood cells break loose and are carried away in the plasma. Such free blood cells continue to divide. Blood islands have been seen in the area vasculosa in the omphalomesenteric vein and arteries, and in the dorsal aorta[WP, unvetted]. uberon posterior ICM UMLS:C1511224 VBI Wikipedia:Blood_island_of_umbilical_vesicle ventral lateral plate mesoderm ZFA:0000094 blood islands EFO:0003489 Region located on the ventral surface of the developing embryo that is a site of hematopoiesis and that is analogous to the yolk sac blood islands of higher vertebrates.[AAO] Nests of developing blood cells arising late in the segmentation period from the intermediate mass, and located in the anterior-ventral tail, just posterior to the yolk extension. Kimmel et al, 1995.[TAO] UBERON:0003061 XAO:0000067 TE:E5.11.2.0.0.0.4 VHOG:0000085 lateral plate mesoderm presumptive structure