How cilia – certain cells' whisker-like projections – synchronise wave movements to enhance their physiological function of fluid pumping
Motile cilia keep things flowing. These cell projections, which line certain tissues, such as those in your nose, periodically beat to move fluid along. In dense carpets of cilia, they coordinate their beats in travelling movements called metachronal waves. How they do this isn’t clear, so researchers investigate in zebrafish noses. Fluorescence microscopy combined with spectral analysis revealed cilia only synchronised locally and the synchronisation area increased in size as the surrounding fluid became thicker. Although synchronisation was local, metachronal waves travelled across the entire multi-ciliated tissue. The direction of these wave patterns was the same across fish but different between left and right nose (pictured) where they were mirror reflections of each other. Computational modelling of wave patterns revealed that their synchronisation prevented cilia (magenta) colliding with each other and improved fluid movement but hardly affected the direction of flow. These waves, therefore, help cilia perform at their best.
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