the tissue swells or shrinks with infusion/expulsion of fluid. This aspect has been introduced into the formulation.

-   The fluid phase, whether slightly compressible or incompressible, can develop compressive stress without bound. However, it can develop at most a small tensile stress [@cavitationchris], having implications for the stiffness of the tissue in tension as against compression. Although this also has implications for void formation through cavitation, the ambient pressure in the tissue under normal physiological conditions ensures that this manifests itself only as a reduction in compressive pressure.

-   When modelling transport, it is common to assume Fickean diffusion [@KuhlSteinmann:02]. This implies the existence of a mixing entropy due to the configurations available to molecules of the diffusing species at fixed values of the macroscopic concentration. The state of fluid saturation directly influences its mixing entropy.

-   If fluid saturation is maintained, void formation in the pores is disallowed even under an increase in the pores’ volume. This has implications for the fluid exchanges between a deforming tissue and a fluid bath with which it is in contact.

-   Recognising the incompressibility of the fluid phase, it is common to treat soft biological tissue as either incompressible or nearly-incompressible [@Fung:1993]. 