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Hair cells from bullfrog saccule B: video showing hair bundle deflection
Autor
Corey, David P.
Assad, John
Resumen
Presente a live hair cell from the inner ear of a bullfrog (Rana catesbeiana), deflected by a glass probe. Protruding from the apical surface of each hair cell is a hair bundle, comprising 50-60 stereocilia and a single kinocilium (identified by its bulbous ending) to which the probe is attached. Stereocilia have stiff cores of cross-linked actin filaments and taper where they insert into the apical surface, so that they remain straight and pivot at their bases. Stereocilia are held together near their tips, in a manner that prevents separation but allows sliding. The molecular basis of this sliding adhesion is not understood. Extending between the tip of each stereocilium and the side of its taller neighbor is an extracellular 'tip link,' not visible in light microscopy. Deflection of a hair bundle towards the tallest stereocilia increases tension in tip links and pulls open mechanosensitive ion channels in the tips of stereocilia. Ion influx then depolarizes the hair cell to create a neural signal. scale: tallest stereocilia are 8 micrometers in height Componente Curricular::Educação Superior::Ciências Biológicas::Biologia Geral