Heart Physiology, Cardiac Autonomy, Electrocardiogram

Abstract

Blood only fulfills its complex functions when constantly in motion. The muscle tissue is considered the functional element of the heart. Composed of interlaced myocardial fibers—myocytes encased in a common sarcoplasmic membrane. In a rhythmic manner, the contracting and relaxing heart emits electrical impulses directed towards the heart's electrical source, pulsating and circling. Since body tissues conduct electricity, it's possible to record the heart's electrical impulses from the body surface using special tools. This method is called electrocardiography, and the graph obtained is referred to as an electrocardiogram. Other components of the conducting system—the atrioventricular node, left and right bundle branches, and their ramifications—the Purkinje fibers, conduct impulses at a high speed of up to 2 m/s. As a result, the left and right ventricles nearly contract simultaneously. Each of the atypical myocardial fibers forming the conducting system has the ability to generate impulses independently or automatically.