Additional myocardial cells are added to the outflow tract during heart looping.Ĭardiac Jelly: gelatinous connective tissue separating the myocardium and heart tube endothelium.Įndocardium: forms from the endothelium of the heart tube.Įpicardium: develops from mesothelial cells arising from the sinus venosus which spread cranially over the myocardium.Ĭross-section through the ventricular section of the heart tube
Myocardium: forms from splanchnic mesoderm surrounding the pericardial coelom. The embryonic vascular system is discussed in further detail here. As the embryo folds, the cranial ends of the dorsal aortae are pulled ventrally until they form a dorsoventral loop: the first aortic arch arteries. In the previous animation you saw that the dorsal aortae develop concurrently with the endocardial heart tubes and form a cranial connection with the endocardial heart tubes prior to folding. The sinus venosus is also divided into two parts: the right horn of the sinus venosus and the left horn of the sinus venosus.īy day 22, coordinated contractions of the heart tube are present and push blood cranially from the sinus venosus. After fusion, constrictions and dilations appear in the heart tube, forming the following divisions (listed from cranial to caudal position):
0 kommentar(er)
