Biology Reference
In-Depth Information
parameters (for example, with or without internal viscosity terms) were then compared with
the real behaviour of the cells. The recoil behaviour of the real system was very similar
whether the laser 'shot' hit a boundary or passed through the middle of a cell. This could
be reproduced only by models in which the forces generated by the cell edges were in fact
smaller than forces contributed by visco-elastic tension in the bulk cytoplasm. For the system
studied, at least, the convergence of experimental observation and computer modelling
demonstrated that boundaries are not everything, and that the internal forces discussed in
Chapter 5 of this topic are very important.
CONCLUDING REMARKS
This chapter is not intended to provide a comprehensive reviewof physical andmathemat-
ical models of epithelial morphogenesis. What it has done instead is illustrated a fewexamples
of common approaches, choosing examples that connect closely enough with experimental
practice that they are genuinely useful. Each example of computer modelling discussed chal-
lenges a 'common-sense' assumption
d
for example that contact inhibition reduces rather than
encourages invasive behaviour, or that the most important forces in an epithelium come from
the cell boundaries. For morphogenesis, this is where the greatest value of modelling lies.
'Common sense' is highly fallible when faced with complex systems; rigorous modelling
can save a great deal of time that would otherwise be wasted following fallacies.
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