Specialized conduction tissue in the interventricular septum; divides into the right and left branches. (#5)

Where the electrical signal arises in normal sinus rhythm. (#1)

The electrical signal spreads from the conduction tissue in the atria to this structure. It slows the signal for a short time to allow the atria to contract before the signal is sent to the ventricles. (#2)

Fast-conducting fibers that spread the electrical signal throughout the ventricular wall (#3)

Where the electrical signal arises in nodal rhythm at a rate of 40-50 BPM. (#2)

Fibers that spread the electrical signal throughout the atrial wall (#6)

These carry the signal from the bundle of his to the purkinje fibers. (#4)