regional_part_of Conducting system of right atrium Conducting system of left atrium Subdivision of conducting system of heart Conducting system of interatrial septum Conducting system of heart Sinuatrial node Cardiac pacemaker FMA:9477 Koch's node Node of Keith-Flack SA nodal muscle tissue SA node Sinoatrial node Sinu-atrial node Sinuatrial nodal muscle tissue Sinus node Sinus node of Keith and Flack Subdivision of conducting system of heart at the junction of the right atrium and the superior vena cava, around the sinoatrial nodal branch of right coronary artery and is continuous with the internodal tract. fma