The first septal artery supplying a large part of the ventricular septum, the right bundle branch and the bundle of His. The atrioventricular node (av node) is supplied in this case only by the atrioseptal nodal artery (named also as atrioventricular node artery or “James artery”.
Take your time and watch the relationship between this vessel an the pulmonary valve(pv) and the moderator band.
The left anterior descending artery is marked with arrows.

Image #162