[Model of epithelial morphogenesis based on elastic forces and cell contact polarization]

It is well known that in embryonic tissues at the key stages of morphogenesis there arise stable, stage--specific tension fields. These fields occur due to particular pattern of morphologically polarized cells. Some basic properties have been understood previously. 1. Morphologically polarized and isotropic shapes correspond to the alternative stable states of embryonic cells. 2. Polarization can be transmitted between the adjacent cells via intercellular contacts. 3. The tension fields at particular stage of development determine the pattern of morphogenetic movements. In this paper the physical model is suggested which interprets the selforganization of tension fields in embryonic tissues. The polarization in some region of tissue is assumed to generate the elastic tension in the surrounding cells thus restricting the propagation of cell polarization. It is shown that the properties underlined are sufficient to provide spontaneous subdivision of the cellular layer into the domains of polarized and unpolarized stretched cells. The proportion of polarized and unpolarized areas is determined and size--invariant.