Hair does more than keep you warm. Without the tiny whiskery cells carpeting the inner ear, we would be completely deaf. Each hair floats in a fluid-filled chamber called the cochlea. As sound waves slosh this liquid about, the hairs transmit movement to their companion cells and onto the brain. Despite this vital role, the ear has a pretty minimalist workforce. Compared to the millions of cells dedicated to sensing smells and light, just 15,000 hair cells exist to create our sonic landscape. In reality, this number gets even smaller as most act as amplifiers – only a fifth of hair cells actually detect and transmit sounds. Activity of a specific gene that’s been engineered to glow, colours the cells green just above the black region in this mouse's inner ear. Animals without this gene suffer hearing defects, although exactly why still has scientists pulling their hair out.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences 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.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.