文档介绍：组织胚胎学课件 七年制英文医学班专用
中国医科大学
基础医学院
组胚—英文教学组
Chapter 27 Development of circulatory system
Formation of primitive cardiovascular system
1) extra-embryonic blood vessels
---blood island: at the middle of 3rd week, wall of the yolk sac mesenchyma proliferate and form isolated cell clusters, the peripheral cell e flattened and differentiate into endothelial cell to from endothelial tube; central located cells are detached and develop into primitive blood cells(blood stem cell)
---endothelial tube approach and fuse with each other to form an endothelial work
---endothelial work appears in chorionic membrane and body stalk, and connect to vitelline circulation
2) intra-embryonic blood vessels
---by the 18-20th days, endothelial work appears in intraembryonic mesenchyma to form intraembryonic endothelial work
---by the end of 3rd week, intraembryonic and extraembryonic endothelial works connect to each other to form a diffuse endothelial work
---endothelial works fuse or disappear to form primitive cardiovascular system
---primitive cardiovascular system:
/heart tube: paired, by the 4th week, which fuse
/arteries:
-dorsal aorta:
-vitelline artery
-umbilical artery
-aortic arch: 6 pairs
/veins:
-anterior cardinal vein
-posterior cardinal vein
-common cardinal vein
-vitelline vein
-umbilical vein
2. Development of heart
1) Formation of primitive heart
---cardiogenic plate: proliferation of splanchnic mesodermal cell to form a pair of longitudinal cell cord, then differentiate into cardiac tube
---pericardiac coelom: space in mesoderm
---rapid growth of brain vesicles pulls the opharyngeal membrane, the cardiogenic plate and pericardiac coelom forward
---lateral folds of the embryo make the two cardiac tube approach and fuse with each other