What part of the heart's conduction system initiates the heartbeat?
a. atrioventricular node (AV)
b. sinoatrial node (SA)
c. purkinje fibers
atrioventricular bundle (Bundle of His)
Answer: b. sinoatrial node (SA)
The sinoatrial node (SA) initiates the heartbeat from within the right atrium. The electrical impulse then passes along through the atrioventricular node (AV) to become delayed slightly before passing to the ventricle to cause the contraction, or heartbeat.