The pacemaker of the heart is characterized by _______

Correct option is D

Ans (d)
Sol. Arch of aorta: The arch of the aorta is a part of the circulatory system that carries oxygenated blood from the heart to the rest of the body. It is not involved in the generation of the heart's electrical impulses.
Bundle of His: The Bundle of His is part of the heart's conduction system that carries electrical impulses from the AV node to the ventricles. It is involved in transmitting impulses but does not act as the heart's pacemaker.
AV node: The AV (atrioventricular) node is responsible for delaying the electrical impulse before it passes to the ventricles, allowing the atria to contract fully. While it is part of the conduction system, it is not the primary pacemaker.
SA node: The SA (sinoatrial) node, located in the right atrium, is the natural pacemaker of the heart. It initiates electrical impulses that regulate the heart's rhythm.