Final answer:
The process of the heart muscle resetting and initiating an organized rhythm is called sinus rhythm. This is controlled by the heart's pacemaker cells which possess autorhythmicity, and ensures coordinated contractions and effective blood pumping. In cases of arrhythmias, artificial pacemakers or defibrillators may be used to restore sinus rhythm.
Step-by-step explanation:
When the heart muscle resets and initiates an organized rhythm, it is referred to as sinus rhythm. This rhythm is the normal, rhythmic beating of the heart and is established by the heart's pacemaker cells located in the sinoatrial (SA) node. These cells have the capability of automaticity, known as autorhythmicity, meaning they can generate electrical impulses without external control from the nervous or endocrine systems. These impulses are essential for the synchronised contractions of the heart's atria and ventricles, allowing for effective blood pumping.
Cardiac pacemaker cells depolarize at regular intervals, which determines the heart rate. The electrical signals they produce first cause the atria to contract and then, after traveling through the atrioventricular (AV) node, cause the ventricles to contract in a coordinated manner. This sequence of events ensures that blood is pumped efficiently throughout the body.
In cases of heart arrhythmias, which are abnormal heart rhythms, treatment options like artificial pacemakers or cardiac defibrillators may be utilized. An artificial pacemaker is used to restore the heart's rhythmic contractions or sinus rhythm by delivering regulated electrical impulses.