Example of single cell to whole tissue modalities for the myometrial physiome. (A) The net ionic current flowing across an uterine myocyte in unit time is the sum of many individual currents measurable by voltage clamp electrophysiology. The net current flow (equation ) and the cellular fluxes of intracellular Ca2+ (equation ) can be modeled by differential equations. (B) Mathematical descriptions of particular ion channel characteristics can contribute to the construction of biophysically detailed models of cell excitability. Here, the inward Na+ current data of  (open circles) can be stringently modeled as depicted by the solid line. (C), this information at the single cell level must, in due course, be extended to provide a rigorous model to explain tissue level function such as that depicted here – periodic fluctuations in membrane potential, intracellular Ca2+ and force occurring in situ (adapted from ). KIR, Kv, KATP, KCa refer to inward rectifying, voltage-, ATP- or Ca-dependent K channels, respectively. Vm, membrane potential. Cm, membrane capacitance. SR, sarcoplasmic reticulum. RyR, ryanodine receptors.