PLAYING BY EAR

Here is Nik Wallenda, 450 metres above the Little Colorado River in Grand Canyon - playing it by ear again.                    

 

Okay, he’s using his arms and legs with assistance from a balance rod to pull off his stunt ‘safely’ but we’re left wondering what he’s got between those ears.                

We’ll never really know except, like the rest of us, he must have two of these peculiar thingummies:

Whatever is this anyway?

No it’s not a three-headed snail and no, it’s not a tumor.                                

This is your inner ear that some medicos say evolved over millions of years, so let’s go exploring inside Nick’s ear like a bug…but this ain’t easy…a waxy substance is making this adventure hard-going and soon we come to a membrane completely blocking our way.

We learn that the membrane is the eardrum which receives sound vibrations that are amplified behind in the middle ear by 3 tiny bones: the ossicles (malleus, incus & stapes). Why 3?...so that loud sounds are dampened. Clever hey!...and yet another example of ‘irreducible complexity’ - leave any component out and nothing works.     

Now remember the good old days of flying when the hosties would hand out lollies to passengers?...except you were busy with ear-ache as we descended to our destination in an unpressurised airliner. The Eustachian tubes normally vent the middle ear to the throat, which prevented Nick’s ear-drums from perforating with the pressure changes when driving up to the Grand Canyon rim at about 4000 feet above sea level.

At last we reach the inner ear where the stapes vibrates an oval window in the cochlea (‘the snail shell’), sending waves thru fluid which are detected by hairs (organ of Corti), sending electrical signals for the brain to interpret as sound.

Wait!...that’s not all. The 3 semi-circular canals you can see are set at right angles to each other and contain fluid that moves tiny hairs, enabling the brain to sense movement of the body….and there’s more vestibular organs! The brain needs a reference to distinguish between movement of the body and attitude of the head so there are two sensors incorporated as well: the saccule aligned vertically and the utricle aligned horizontally.

So ladies and gentlemen, just what are we born with, between those lugs?  

Two integrated, self-cleaning, pressure tolerant, water-resistant, shock-proof, dual purpose, attenuating stereophonic microphones – complete with artificial horizons and 3-dimensional accelerometers!             
If just one component was missing would the ear be a masterpiece of bionic engineering?..... or just a ridiculous deformity for hanging your specs on?           

 

 

Acknowledgements:  
Anatomica, Global Book Publishing, Sydney 2000  
wikipedia.org    
medicinenet.com   
Gillen, A. ‘Body By Design’, Master Books, Green Forest AR, 2001  
Photo credits:   
nydailynews.com      
3dscience.com  
zrhbzeds.homeip.net