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]. [ http://en.wikipedia.org/wiki/Sinoatrial_node http://amigo.geneontology.org/amigo/term/GO:0003163 ]
Synonyms: sinus node cardiac pacemaker SA node sinus node of Keith and Flack sinuatrial nodal muscle tissue nodus sinuatrialis SA nodal muscle tissue sinoatrial node sinuatrial node node of Keith-Flack sinu-atrial node Koch's node
- UMLS:C0037189 (ncithesaurus:Sinoatrial_Node)
uberon_slim, pheno_slim, vertebrate_core
WP:Heart states: "The SA node is found in all amniotes but not in more primitive vertebrates. In these animals, the muscles of the heart are relatively continuous and the sinus venosus coordinates the beat which passes in a wave through the remaining chambers. Indeed, since the sinus venosus is incorporated into the right atrium in amniotes, it is likely homologous with the SA node. In teleosts, with their vestigial sinus venosus, the main centre of coordination is, instead, in the atrium.". Note however that ZFA has SA node.