Figure 3.

Developmental origins of the outflow tract and other regions of the heart. The first heart field (red) gives rise to the primitive heart tube and eventually the left ventricle, the atria, and a part of the right ventricle. The second heart field (blue) gives rise to the outflow tract, the right ventricle and a part of the atria. The cardiac neural crest (yellow) gives rise to the outflow tract cushion that eventually forms the outflow tract septum. The proepicardial organ (green) gives rise to the epicardium.