Final answer:
The statement is true. The sinoatrial (SA) node regulates the heart's cardiac conduction system and holds the highest inherent depolarization rate, serving as the natural pacemaker for initiating normal cardiac rhythm.
Step-by-step explanation:
The statement that the cardiac conduction system is normally regulated by a population of pacemaker cells known as the sinoatrial (SA) node is true. The SA node is crucial in establishing the normal cardiac rhythm, as it has the highest inherent rate of depolarization amongst the heart's conductive cells. Hence, it is often referred to as the heart's natural pacemaker. This node initiates the sinus rhythm, which is the normal sequence of electrical impulses followed by muscular contraction in the heart.
The SA node generates an action potential that spreads across the atria, causing them to contract. The electrical impulse then travels to the atrioventricular (AV) node, where there is a slight delay. This delay ensures that the atria have enough time to pump blood into the ventricles. After the delay, the impulse moves through the AV bundle (bundle of His), divides into bundle branches, and eventually reaches the Purkinje fibers, leading to the contraction of the ventricular muscle fibers.
Different parts of the conduction system can initiate their own impulses, but the rate at which these impulses are generated decreases as you move away from the SA node. For example, in the absence of the SA node, the AV node would next assume the role of pacemaker, but at a slower rate. This hierarchical structure ensures that the SA node normally controls the heart's rhythm due to its faster rate of depolarization compared to the rest of the cardiac conduction system.