Another spiral; this time, one that can be found inside the human body:
An isolated and dissected cochlea.
The cochlea is the organ inside your inner ear that ultimately transforms the vibrations of sound into nerve signals, which are sent to the brain and thus "heard". Essentially, it is a spiral-shaped, hollow bone, filled with fluid and lined with hairs. The coiled shape of your cochlea allows you to hear a wider range of frequencies than animals with a straight cochlea.
Different frequency waves peak at different positions along the tube. Hair cells sitting on the basilar membrane sense these motions by bending against the membrane and produce electrical signals that feed into the auditory nerve. Hair cells near the large end of the cochlea detect high-pitched sounds, such as the notes of a piccolo, while those at the narrow end of the tube detect lower frequency sounds, like a the oompah of a tuba.
Only mammals have developed the coiled shape; the cochlea of birds and reptiles is straight and less efficient.
Image via the Ethnomusic Department at UCLA
More like this
The cochlea is the snail-shaped organ that mammals use to perceive and transduce sound, and is located deep in the inner ear.
If you read the 'About' page, or anything about me, you probably noticed that I work on hair cell regeneration in the cochlea. But, perhaps, some readers are not familiar with the machinations of the inner ear.
Many of my SciBlings have been doing posts on "basic concepts" in their fields of expertise.
... like, when you hear it on playback from a tape recorder.
I wouldn't go as far to say birds have less efficient cochleae, as they can regenerate hair cells, and we can't. :)
In this case, I was referring simply to the spiral form of the cochlea, which is more efficient for the transmission of sound. The birds certainly have an advantage... Our ear is sort of like the fancy import car which can potentially go faster, while the birds have the reliable domestic model, which can be repaired. If I had a choice, I'd take the reliable and less attractive model. :)
"A spiral form... efficient for the transmission of sound". What a coincidence! Well for many of you this might be common knowledge, but a week ago, when an old friend sent me the link it was quite new to me: http://www.bowers-wilkins.co.uk/display.aspx?infid=1729&terid=2003 .
Oh, I don't consider buying and I doubt anybody needs 8 power amplifiers to listen to the perfect playback. Our human spiral may be very sensitive to quality, but mine can be nicely satisfied with much more affordable playback technology. Even so I was very impressed with this spiral set.
But doesn't this carry the same inherent flaw as globalization...one site gets compromised and due to their interconnectivity they ALL get compromised...