EMBRYONIC BASIS OF MORPHOGENESIS OF ARTERIAL SKELETON IN HUMAN QUASI-SEGMENTАRY BODY
Cardiovascular and nervous systems begin their development in epiblast of human emryo, where are formed angioblast, original source of endotheliocytes, and neural ectoderm, source of development of all nervous system in form of neural plate аnd then neural tube. Subsеquently neural tube and most part of its derivatives remain in limits of epiblastic derivatives (in soma). Yet before appearance of neural plate cells of angioblast migrate in primitive streak and then in mesoderm, from which move out in form of mesenchymal cells, extending into all layers of forming body of embryo. These cells form anlages of heart and vessels, growing to all organs, provisional and definitive. Moreover cells of angioblast pass through primitive streak yet before anlage of heart, which begins yet before formation of chordа and neural plate, аnd primitive streak (or notochord, chordа) induces anlage of neural plate. Тhus, and chordа, and arteries, subsequently determing segmentary structure of human body, spring in any case just from primitive streak.