Microscopic studies on chick thrombocytes in early development.
Thrombocytes of early chick embryos were observed in blood smear and whole embryo preparations stained with PAS. In the blood smear preparations, thrombocytes usually had one large glycogen mass in the cytoplasm until 3 days of incubation, and it became progressively smaller with the advance of embryonal development. While, the application of PAS to whole embryo preparations was shown to be a very useful method for observation of the blood cells in embryos at early stages when their blood could not be collected. Thrombocytes were clearly identified in situ in the embryo by PAS staining even in very early stages when no blood circulation occurred. At stage 12, distribution of the thrombocytes coincided with that of blood islands, but was limited within the area opaca. Mitotic figures of the thrombocytes were frequently found in and near the blood islands. This suggests that blood islands are the proliferation sites of the thrombocytes in early chick embryos.
D000818:Animals; D001792:Blood Platelets / Q000032:analysis / Q000166:cytology*; D002642:Chick Embryo / Q000166:cytology*