Figure 2.

Schematic diagram illustrating the components involved in the whole-cell model framework. Displayed are the ionic conductances and their respective interactions with the pacemaker units and the bulk cytoplasm. Included are a population of n_PU pacemaker units, each of which has a transmembrane ionic flux contribution denoted by I_ion(PU). The two types of intracellular Ca²⁺ fluxes responsible for Ca²⁺ movements throughout the bulk cytoplasm are 1), the intercytoplasmic/pacemaker unit Ca²⁺ flux from each pacemaker unit (J_S2Cy), and 2), the bulk cytoplasm intracellular Ca²⁺ flux (J_Cy). Also included are six plasma conductances that regulate cellular electrophysiology: 1), the T-Type Ca²⁺ current (I_Ca(T)); 2), the Ca²⁺ extrusion pump (I_Ca(Ext)); 3), the K(v1.1) K⁺ current (I_K(v1.1)); 4), Ether-a-go-go (ERG) K⁺ current (I_K(ERG)); 5), a background K⁺ leakage current (I_K(B)); and 6), a nonselective inward leakage current (I_L).