An analysis of the relation between membrane structure and viscoelastic properties, in particular in the transversal direction. Hianik and Passechnik's approach is fundamentally different from the usual one, in that they analyze lipid bilayer dynamics during various modes of deformation, arriving at a new, "three-layer" model that accounts for the great heterogeneity of biomembranes. The macroscopic parameters of membranes have been measured using a wide variety of methods, leading to a discussion of the correlations between the parameters. There is also a discussion of the dynamic changes in mechanical properties of lipid bilayers in the course of conformational transition of integral proteins. During the conformational changes of proteins, the structure of a bilayer undergoes a transition, reaching a stable membrane state.