Fig. 2.

An illustration of a strand of idealized cells (A), a possible multiscale representation (B), and the corresponding numerical discretization (C). In the multiscale model, the thick line represents the unresolved subdomain over which the macroscale model applies. Notice that this subdomain ignores the cellular microstructure. The disjoint thin lines represent the individually resolved cells over which the microscale model applies. Space for clefts is drawn for clarity, even though the model idealizes them as having no width. The boundary between the resolved and unresolved regions is called the coarse-fine interface. The computational grid in C is broken into blocks of m = 2 myocytes. When unresolved, a block is described by a single node. When resolved, each myocyte within the block is represented by n = 5 interior nodes and two boundary nodes located at the ends of the myocytes that, for clarity, are not depicted.