Mechanism helps explain the ear's exquisite sensitivity

[Jim__]

From phys.org:

This diagram depicts how the tectorial membrane works to enhance hearing. The pistons at top and bottom depict how variations in the fluid pressure within the inner hear, which causes bundles of microscopic hairs (depicted as the black structures in the gap at top, to move, each of them tuned to different frequencies of sound. The tectorial membrane, whose unusual properties the team studied, is the gray shaded structure at top. Credit: MIT micromechanics group

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The human ear, like those of other mammals, is so extraordinarily sensitive that it can detect sound-wave-induced vibrations of the eardrum that move by less than the width of an atom. Now, researchers at MIT have discovered important new details of how the ear achieves this amazing ability to pick up faint sounds.

The new findings help explain how our ears can detect vibrations a million times less intense than those we can detect through the sense of touch, for example. The results appear in the journal Physical Review Letters, in a paper by visiting scientist and lead author Jonathan Sellon, professor of electrical engineering and senior author Dennis Freeman, visiting scientist Roozbeh Ghaffari, and members of the Grodzinsky group at MIT.

Both the ear's sensitivity and its selectivity—its ability to distinguish different frequencies of sound—depend crucially on the behavior of a minuscule gelatinous structure in the inner ear called the tectorial membrane, which Freeman and his students have been studying for more than a decade. Now, they have found that the way the gel membrane gives our hearing its extreme sensitivity has to do with the size, stiffness, and distribution of nanoscale pores in that membrane, and the way those nanopores control the movement of water within the gel.

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[TreasonousBastard]

1. Fascinating. I wonder if more work with cats, bats, dogs, etc...

will give us tricks for super hearing.

BTW, the clickbait down toward the bottom gives news of something more useful right now:

https://phys.org/news/2013-11-university-physicists-urine-splash-back-tactics.html