part_of part of part of capable of capable of capable of part of capable of part of contributes to morphology of regulation of heart rate cardiac muscle contraction conducting system of heart sinoatrial node http://upload.wikimedia.org/wikipedia/commons/d/d2/Sinoatrial_node_low_mag.jpg http://upload.wikimedia.org/wikipedia/commons/d/de/Sinoatrial_node_2_low_mag.jpg sinuatrial node cardiac pacemaker UBERON:0002351 MA:0000097 sinus node of Keith and Flack Koch's node SA nodal muscle tissue ZFA:0005069 NCIT:C33555 TAO:0005069 sinuatrial nodal muscle tissue SA node sinu-atrial node The part of the cardiac conduction system that controls the timing of heart muscle contraction. It relays electrical signals to the AV node[GO]. Subdivision of conducting system of heart at the junction of the right atrium and the superior vena cava, around the sinoatrial nodal branch of right coronary artery and is continuous with the internodal tract[FMA]. EMAPA:35772 uberon MESH:D012849 sinoatrial node node of Keith-Flack EHDAA2:0004184 SCTID:277687007 sinus node FMA:9477 GAID:561 UMLS:C0037189 Wikipedia:Sinoatrial_node BTO:0004358 cardiac muscle of right atrium conducting tissue of heart