Cardiac physiology syncytium, the sinoatrial node, the atrioventricular node, the bundle of His (atrioventricular bundle), the bundle branches, and the Purkinje cells. Normal sinus rhythm is established by the sinoatrial (SA) node, the heart's pacemaker. The SA node is a specialized grouping of cardiomyocytes in the upper and back walls of the right atrium very close to the opening of the superior vena cava. The SA node has the highest rate of depolarization. This impulse spreads from its initiation in the SA node throughout the atria through specialized internodal pathways, to the atrial myocardial contractile cells and the atrioventricular node. The internodal
Blank node the blank node indicates an 'unknown' URI. From a technical perspective they give the capability to: Below there is an example where blank nodes are used to represent resources in the aforementioned ways. In particular, the blank node with the identifier '_:students' represents a Bag RDF Container, the blank node with the identifier '_:address' represents a complex attribute and those with the identifiers '_:activity1' and '_:activity2' represent events in the lifecycle of a digital object. The ontology language OWL uses blank nodes to represent anonymous classes such as unions or intersections of classes, or classes called restrictions, defined by a