How Compressibility Influences the Mechanical Bidomain Model

Abstract

Compressibility influences the mechanical bidomain model describing the elastic properties of the tissue. In this model, the displacements of the intracellular and extracellular spaces are analyzed individually, and differences in these displacements give rise to membrane forces. In our present analysis, two length constants are associated with the membrane spring constant; one contains the shear moduli and the other contains the bulk moduli. The analytical solutions in our examples indicate that the monodomain part does not contribute to the membrane forces. Accounting for compressibility has its largest impact on the intracellular and extracellular pressures. The bidomain contribution to the pressure obeys the Helmholtz equation rather than Laplace’s equation. This model helps us to estimate the membrane forces that cause tissue remodeling and mechanotransduction.