Table 2.01 - Early Heart Development:

Cardiac Primordium:

Arises from cardiogenic plate (splanchnic mesoderm) lying in front of head, beneath pericardial chamber

Head (neural plate) grows forward, reversing orientation, to below foregut, above pericardial coelom

Caudal end continuous with mesoderm; receives veins there

Cardiac Tube:

Two longitudinal strands of mesodermal cells, each forming cavities

Thin-walled endothelial tubes within splanchnic mesoderm; begin fusing first at cranial end into a single tube

Internal endothelial tissue becomes future endothelium lining; external, thick covering gives rise to myocardium and epicardium

Heart tube suspended by dorsal mesocardium; later disappears.