Guide To The Structure Of The Heart

Electrical System

The electrical system of the heart triggers and regulates the heartbeat in a process known as cardiac conduction. Factors such as exercise, temperature, and hormones influence this process. In the first step of cardiac conduction, nerve impulses are generated by the sinoatrial node. They travel through the entire heart wall, causing both of the atria to contract. In the second stage of conduction, the nerve impulses reach the atrioventricular node and are delayed for roughly one-tenth of a second. This delay triggers atrial contraction, and blood from the atria is emptied into the ventricles. Next, the nerve impulses travel from the atrioventricular node to the atrioventricular bundle, and they are carried to the left and right ventricles and the center of the heart. As the impulses travel down the atrioventricular bundle, they eventually reach the Purkinje fibers and trigger the contraction of the ventricles. Cardiac conduction controls the cardiac cycle, the sequence of events that occurs when the heart beats. In the diastole phase of the cardiac cycle, the atria and ventricles are relaxed, and blood flows into them. During the systole phase, the ventricles contract, allowing blood to be sent from the heart to the rest of the body.