Embryonic Epicardium Progenitors Origin

Stages during epicardium development.

Top: Transverse cross-section of the lower pharyngeal arches and developing heart is presented and shows the epicardium-forming progenitor cells (i.e., proepicardium), which arise from the splanchnic mesoderm.

Bottom: A magnification of the differentiated proepicardium cells that become the outer layer of the heart, the epicardium enveloping the myocardium with relation to the most inner layer being the endocardium.

The lateral view presented in the upper panel shows stage 14-15 chick embryo.