part of part of has part has part contributes to morphology of Purkinje myocyte transitional myocyte myocardial endocrine cell myocyte of sinoatrial node myocyte of atrioventricular node heart myocardium conducting system of heart heart conduction system EHDAA2 divides the system from the tissue SCTID:281489000 The fish heart displays clear polarity of contraction in a posterior-to-anterior direction. The contraction waves originate in the sinus venosus and terminate in the conus arteriosus. The nodal phenotype persists in the inflow region of the heart, varying from the venosinus to the sinoatrial junctional areas in different species . Similar to the mammalian situation, pacemaker tissue with a lower intrinsic rhythmicity is also found at the atrioventricular junction.[uncertain][VHOG] central conduction system impulse conducting system VHOG:0001271 systema conducente cordis EMAPA:35428 MESH:D006329 FMA:9476 cardiac conduction system EFO:0003909 cardiac conducting system MA:0000094 UBERON:0002350 cardionector ZFA:0005063 TAO:0005063 EV:0100025 EHDAA2:0004185 complexus stimulans cordis The cardiac conduction system consists of specialized cardiomyocytes that regulate the frequency of heart beat[GO]. cardiac impulse conducting system cardiac muscle tissue of myocardium conducting tissue of heart