Final answer:
The sinoatrial (SA) node is the primary pacemaker of the heart, generating the electrical impulses responsible for the heartbeat. It is located in the right atrium and its signals orchestrate the coordinated contractions of the heart's chambers.
Step-by-step explanation:
The primary pacemaker of a normal heart, where the electrical impulse for the heartbeat originates, is the sinoatrial (SA) node. This specialized group of myocardial conducting cells, located in the right atrium of the heart, initiates the sinus rhythm, which is the normal electrical pattern that leads to the contraction of the heart. The pacemaker cells of the SA node generate these electrical signals autonomously due to their ability to depolarize automatically, a characteristic known as autorhythmicity.
Once the SA node creates an electrical impulse, it travels through the heart leading to the contraction of the atria. The signal then reaches the atrioventricular (AV) node, where it undergoes a brief delay before being conducted to the ventricles. This delay ensures the atria have time to fully empty their blood into the ventricles before the ventricles contract, thereby maintaining an efficient and orderly function of the heart.