0 cm CvRL, the trabeculation reached up to epicardium with development of large intercellular spaces and decreased cardiac jelly.
Also  reported in human embryo that at end of 3rd week of gestation the endocardium was lined by endothelial cells which rest on the cardiac jelly layer.
The cardiac jelly lying between the myocardium and endocardium is largely synthesized by myocardial cells.
Distribution of fibronectin, type I collagen, type IV collagen, and laminin in the cardiac jelly of the mouse embryonic heart with retinoic acid-induced complete transposition of the great arteries.
The team reported experiments demonstrating that chick-embryo endothelial cells placed atop a gel layer in a petri dish broke away from their neighbors and started to travel into the gel when exposed to adherons isolated from the cardiac jelly
of embryonic chick hearts.