Übersetzen...
Automatische Übersetzung:
Illustration depicting the heart's electrical system. Annotated are the Sinoatrial node and the atrioventricular node. The sinoatrial (SA) node (thick purple oval upper left) consists of self-excitatory muscle cells that contract rhythmically at around 70 beats per minute. Following each contraction, an impulse spreads through the heart's upper chambers (atria, upper frame) to the atrioventricular (AV) node (thick purple oval opposite SA node). Contraction of the atria causes blood to move into the lower chambers (ventricles, lower frame).