Microscopic hair-like cilia have great responsibility in many parts of our body. Yet they are simply conglomerations of tube-like proteins. Acting like road-sweepers on the cells lining our throat they expunge bacteria ridden mucous into the stomach in coordinated waves. They also play a role in our sense of sight. Each light-collecting cell in our eyes contains a cilium that directs photosensitive pigments to the surface where they detect light. Zebrafish eye development is similar to ours, so they are a useful research model. Normal cilia keep pigments in position (shown in green, left image). But in fish without a gene called IFT88, cilia fall apart and pigment accumulates (swathe of green in the right image). The result is a lethal concentration that destroys the cells. Healthy cilia are equally important in our ears and nose.
Written by Charles Harvey
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences (the new name for the MRC Clinical Sciences Centre) the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.