What is the primary origin of normal electrical impulses in the heart?

The sinoatrial (SA) node serves as the primary origin of normal electrical impulses in the heart, functioning as the heart's natural pacemaker. Located in the right atrium, the SA node generates electrical signals that initiate each heartbeat, setting the rhythm for the entire cardiovascular system. This process ensures that the heart contracts in a synchronized manner, efficiently pumping blood throughout the body.

The SA node's electrical impulses propagate through the atrial myocardium, causing the atria to contract and push blood into the ventricles. Following this, the electrical signals travel to the atrioventricular (AV) node, which serves as a secondary pacemaker and conducts impulses to the ventricles with a slight delay to ensure that the atria have sufficient time to empty before the ventricles contract.

Other structures, such as the Bundle of His and Purkinje fibers, further distribute the impulses throughout the ventricles to ensure coordinated contraction but do not initiate the heartbeat. These components play essential roles in the conduction pathway but rely on the SA node's intrinsic pacing to function effectively. Thus, the SA node is essential for maintaining the heart's natural rhythm, making it the primary source of electrical impulses.