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 围心腔 生心索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