The sites and expansion of intra-embryonic blood islands in the early chick embryo.
The intraembryonic blood islands preceding the hepatic haemopoiesis, were examined in embryos from stage 17 to 19 by light microscopy, and their three-dimentional expansion was demonstrated. These blood islands were located in the mesenchyme of the lateral fold, mesentery, allantois and ventral aorta, commonly showing large scale. Except the lateral fold, however, those were just temporary sites. Particularly large islands were necessarily found in the mesenchyme of the lateral fold at the stages examined. They were present bilaterally and exhibited cephalocaudally long, rod-like structures with variable sizes. The largest island measured over 2,600 microns in length.
Ukeshima
A
A
Kumamoto University College of Medical Science, Japan.
Kudo
M
M
D000818:Animals; D002642:Chick Embryo; D006413:Hematopoietic System / Q000196:embryology*