Question

multiple choice question
heart rate is altered by stimulation of the sa node or the ________.
bundle branches
av bundle
av node
purkinje fibers

Explanation:

The sino - atrial (SA) node is the heart's natural pacemaker. The atrioventricular (AV) node also plays a role in regulating the heart rate by controlling the rate at which electrical impulses are transmitted from the atria to the ventricles. Bundle branches, AV bundle, and Purkinje fibers are mainly involved in the rapid conduction of electrical impulses for ventricular contraction rather than primary heart - rate regulation.

Answer:

AV node