Figure 1.
Proepicardial Field. A) Schematic of an early somite stage chick embryo. Heart precursors occupy bilateral fields within the lateral plate mesoderm. The primary heart field (1°) is indicated in grey, the secondary heart field (2°) is indicated in pink, and the posterior tertiary heart field (3°) is indicated in green. Fate mapping studies indicate the progenitors of the Proepicardium reside outside and adjacent to the tertiary heart field (blue). B) Schematic of a heart tube. The primary heart fields have fused along the midline, while the secondary and tertiary heart field have not yet been incorporated into the heart. The proepicardial precursors maintain their position lateral to the heart field mesoderm (blue). C) Schematic of a looping stage heart. the proepicardium (blue) can be seen extending off the right inflow of the heart. HT - heart tube, At - atria, AVJ - atrioventricular junction, Vt - ventricle, Pe - proepicardium, A - anterior, P -posterior, R - right, L- Left, D - dorsal, V - Ventral.