conducting system (heart, embryology)
Cells of the conducting system of the heart originate from the modification of mesenchymal cells. The sinuatrial node is derived from cells of the sinus venosus. As this is absorbed into the right atrium, the region of the node comes to lie at the junction of sinus venosus and the original atrium. In the mature heart, this is at a point within the sinus venarum near to the aperture of the superior vena cava.
Some of the cells of the atrioventricular node and bundle of His also originate from the primitive sinus venosus towards its left side; others originate from the atrioventricular canal. Eventually, both groups migrate to a position within the interatrial septum.
Last reviewed 01/2018