The role of collective cellular rearrangements in the rheology of dense biological tissues.

In many biological processes, a tissue's ability to deform and flow under shear shear is crucial for physiological function. Despite its importance to the understanding of embryonic development and tumor metastasis, the relationship between how a tissue flows plastically and cellular rearrangements is not well understood. Here, we use the vertex model to study the collective cell rearrangements and the tissue rheological response of a monolayer under external shear. We vary the adhesion and cortical tension of the cells to investigate the effect of this parameter on the tissue response to simple shear. We also construct a mean field model that is able to predict plasticity in experiment and simulations.