An Excitable Contractile Cell

In 1980, Gary Odell, George Oster and coworkers published papers on a mechanochemical model for epithelial invagination (folding of a sheet of cells) in the early stages of formation of an embryo. An attractive feature of this model is that it combines a chemical switch with a simple mechanical element (a spring with variable rest-length). I discuss this model, relate it to our previous experience with biochemical switches, and to the mechanical spring-based systems described in Jun Allard's first lecture. This model also anticipates a later lecture on models for 2D cell motion based on springs and dashpot elements.