Editing Invagination (section)

=== Basal relaxation ===
To maintain a constant cell volume during apical constriction, cells must either change their height or expand the basal surface of their cells. While the process of basal relaxation has been less thoroughly studied, in some cases it has been directly observed that the process of apical constriction occurs alongside an active disassembly of the actin-myosin network at the basal surface of the cell, allowing the basal side of the cell to expand. For example, this has been observed in the ''Drosophila'' ventral furrow invagination<ref>Polyakov, Oleg, Bing He, Michael Swan, Joshua W. Shaevitz, Matthias Kaschube, and Eric Wieschaus. 2014. “Passive Mechanical Forces Control Cell-Shape Change during Drosophila Ventral Furrow Formation.” ''Biophysical Journal'' 107 (4): 998–1010. <nowiki>https://doi.org/10.1016/j.bpj.2014.07.013</nowiki>.</ref><ref name=":4">Pearl, Esther J., Jingjing Li, and Jeremy B. A. Green. 2017. “Cellular Systems for Epithelial Invagination.” ''Philosophical Transactions of the Royal Society B: Biological Sciences'' 372 (1720): 20150526. <nowiki>https://doi.org/10.1098/rstb.2015.0526</nowiki>.</ref> and the formation of the [[otic placode]] in the chicken.<ref>Sai, XiaoRei, and Raj K. Ladher. 2008. “FGF Signaling Regulates Cytoskeletal Remodeling during Epithelial Morphogenesis.” ''Current Biology'' 18 (13): 976–81. <nowiki>https://doi.org/10.1016/j.cub.2008.05.049</nowiki>.</ref><ref>Sai, Xiaorei, and Raj K. Ladher. 2015. “Early Steps in Inner Ear Development: Induction and Morphogenesis of the Otic Placode.” ''Frontiers in Pharmacology'' 6 (February). <nowiki>https://doi.org/10.3389/fphar.2015.00019</nowiki>.</ref>