Umbilical Cord and Major Fetal Vessels

摘要: The development of the umbilical cord is closely related to that amnion (see Chapter 7). Throughout last days 2nd week p.c. blastocystic cavity filled by a loose meshwork mesoderm cells, extraembryonic mesoblast, which surrounds embryoblast (Figure 115). composed two vesicles: amnionic vesicle and primary yolk sac. Where these vesicles are in contact with each other, they form double-layered embryonic disk. During following cells rearranged such way line inner surface trophoblastic shell, as chorionic mesoderm. They also cover Between layers exocoelomic forms. It largely separates embryo its mesodermal from exocoelom bridged only one place, lies basal vesicle.