Sinoatrial node is influenced by nerves that supply it. The sinoatrial node is a banana-shaped structure that varies in size, usually between 10-30 millimeters (mm) long, 5–7 mm wide, and 1–2 mm deep. The SA node is located in the wall (myocardium) of the right atrium, laterally to the entrance of the superior vena cava in a region called the sinus venarum (hence "sino-" + "atrial)". It is positioned roughly between a groove called the crista terminalis located on the internal surface of the heart and the corresponding sulcus terminalis, on the external surface. These grooves run between the entrance of the
Node influence metric probabilities. The accessibility has been shown to reveal community structure in urban networks, corresponds to the number of nodes which can be visited in a defined time period, and is predictive of the outcome of epidemiological SIR model spreading processes on networks with large diameter and low density. The expected force measures node influence from an epidemiological perspective. It is the expected value of the force of infection generated by the node after two transmissions. The expected force of a node formula_4 is given by where the sum is taken over the set formula_9 of all possible transmission clusters resulting