part of part of connected to connected to contributes to morphology of Homo sapiens system interatrial septum conducting system of heart atrioventricular node http://upload.wikimedia.org/wikipedia/commons/5/50/ConductionsystemoftheheartwithouttheHeart.png http://upload.wikimedia.org/wikipedia/commons/9/92/Gray501.png MAT:0000498 NCIT:C32161 BTO:0005689 FMA:9478 atriovetricular node Wikipedia:Atrioventricular_node nodus atrioventricularis UMLS:C0004247 AV node ZFA:0005070 node of Tawara UBERON:0002352 atrioventricular nodal muscle tissue atrio-ventricular node EFO:0000276 GAID:558 A-V node TAO:0005070 Three major adaptations, or 'novel cardiac components', that were not present in the ancestor chordate heart tube can be distinguished in the lower vertebrate heart: the atrium, ventricle, and possibly the muscular sinus venosus. Furthermore, within the ventricular component a compact outer myocardial component and an interiorly localized extensive trabecular component can be distinguished. The specific activation of the ventricle adds to its complexity as follows. The depolarizing impulse travels rapidly from the atrioventricular node toward the apex and then toward the conal region, achieving activation from apex to base.[uncertain][VHOG] nodus atrioventricularis EMAPA:35153 MESH:D001283 EHDAA2:0004183 Aschoff-Tawara node MA:0000095 downstream pacemaker An area of conducting tissue between the atria and the ventricles of the heart that conducts the normal electrical impulse from the atria to the ventricles. VHOG:0001474 SCTID:277688002 AV nodal muscle tissue cardiac muscle tissue of interatrial septum cardiac muscle tissue of myocardium crista terminalis conducting tissue of heart