A Balancing Act

A Balancing Act

Nature’s Gyroscope: Your ear does much more than hear. While the snail shaped cochlea of the inner ear (pictured below) is superbly adapted for picking up sound vibrations (by deflections of hair cells described in last week’s post), the rest of the inner ear is a complex labyrinth of tubes and chambers that keeps our lives in balance. 

Up, Side and Down: Since we live in a three dimensional world, we have three fluid-filled semicircular canals arranged at right angles to each other, along the x, y and z planes. Each semicircular canal senses a different movement of our head: up and down, side to side, and tilt. When we move our head, the fluid inside the canal moves and presses on a tear shaped bulb at one end. The bulb (ampulla) has a collection of mechanically sensitive hair cells embedded in a jelly like matrix. Deflection of the “hairs” triggers a message to the balance center of our brain that is interpreted as a deflection of the head. Because we have a pair of ears, the deflections are mirror images so that when one side is stimulated the other is simultaneously inhibited by the movement.  

Rolling Stones: Two other chambers sense horizontal and vertical accelerations of your body. The saccule detects changes in vertical movement (when you are in an elevator), and the utricle monitors horizontal movement (as when a car suddenly moves forward or stops). While these organs also have mechanically sensitive hair cells, what is different is a special overlaying membrane weighted down with tiny stones of calcium carbonate, around a protein core, called otoconia. A shearing effect of the membrane against the hair cells detects vertical and linear accelerations of your body.  Sometimes, the otoconia fall into one of the semicircular canals (see image) sending conflicting signals to the brain, resulting in vertigo. Fortunately, a series of head maneuvers can restore the rolling stones back into place. Ménière’s Disease is a common cause of vertigo, accompanied by hearing loss and tinnitus. It is thought to be caused by disturbances in the fluid volume filling the inner ear. Future relief from vertigo may come from prosthetic devices, similar to a cochlear implant in the inner ear. See Physician Inventors Discuss First Device to Combat Vertigo

Space Jellies: Did you know that NASA has been sending jelly fish out to space since the 90’s for microgravity research? Jellies born in space have trouble orienting and swimming back on Earth because their gravity sensors, crystals of calcium sulfate much like our otoconia, fail to develop properly. Read more: http://goo.gl/Jtj00N

A follow up on How Hearing Happens: http://goo.gl/lEHKjF

#ScienceSunday  

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76 Responses to A Balancing Act


  1. And ofcourse equally wonderful the explanation from Rajini Rao

  2. Rajini Rao says:


    Thanks, Kashif Ansari 🙂


    Shaker Cherukuri I read somewhere that up to 60% of the population has experienced vertigo at some time or other. Lucky it has gone now! 


  3. Is the displacement of otoconia also responsible for motion sickness? My wife has motion sickness.

  4. Jean Donahue says:


    If I try and lay flat on my back I get terrible vertigo and nausea. I even passed out once from it.

  5. Rajini Rao says:


    youis Roland J. Ruttledge , hope you keep your balance 🙂


    Kashif Ansari several possibilities for motion sickness. Input from our eyes play an important part in this. For example, if she is looking through a side window of a car, then her eyes tell the brain that she is turning but her ears sense forward movement. The mixed signals trigger nausea and other physiological responses. Also, when one’s head moves in a car/bus, a signal goes to the eyes to automatically compensate for this. But if you force your eyes to focus on something like a book, then again mixed signals result. There are probably many other reasons for motion sickness. I’m terribly prone to it too 😦

  6. Rajini Rao says:


    Dena Ricketts , Jean Donahue I sympathize! My family are particularly prone to nausea at the slightest trigger. Guess who cleans up?? 


  7. i believe just like vertigo we get while ascending and coiling around a mountain, we experience Sea Sickness which is also associated to the same stato acoustic organ being disturbed in our ear while we travel on rough seas,


  8. Neat…I think that explains why she feels better when closing her eyes or while sleeping during travel

  9. Rajini Rao says:


    Haha, I’ll try it next tie Dena Ricketts .


    guruprasad .g.l , when I was  a girl I routinely got motion sickness on those winding bus rides up the Western Ghats to get to Mangalore and the west coast. 

  10. Rajini Rao says:


    Laurent DUBET , what an interesting idea..balance as our sixth sense! Thanks 🙂


  11. The winding road reminds me the route to Rohtang pass from Manali…my wife had to sleep through the journey and missed the scenic beauty of the route

  12. Rajini Rao says:


    Beautiful and dangerous, Kashif Ansari . Here is a pix for anyone interested: http://goo.gl/rWG30Z

  13. Chad Haney says:


    Nice follow up to your hair cell post.

  14. Rajini Rao says:


    Chad Haney , that’s when I had the idea. Thanks 🙂


  15. Yes dangerous too…scary part was when military trucks use to come from the opposite side on a narrow road…


  16. Yeah me too, even now when I go to nandi hills, or when I travel to chikmagalur/DK, my ears respond by rhythmically closing and opening according to the air pressure, very disturbing,

  17. Rajini Rao says:


    According to this article, here is what to do when the pressure in your ear builds up uncomfortably: 


    * Hold your nose, close your mouth


    * Turn your head to the right until your chin touches your shoulder


    * Swallow hard until your left ear pops


    * Turn your head to the left until your chin touches your shoulder


    * Swallow hard until your right ear pops


    * Continue doing this until you reach cruising altitude and start again as the plane begins its approach


    I’ll have to try it next time! Source: http://gizmodo.com/why-your-ears-pop-and-what-to-do-if-they-dont-505598950


  18. Hey thats great…will try next time on a plane


  19. Speaking of up side and down, and on a slightly tangential note, you might enjoy this. Its gets quite interesting at around 3:30…. (but watch all for the experience). http://youtu.be/5ECJcu3mjnE

  20. Rajini Rao says:


    Thanks, Michael MacLauchlan ..listening now. I’ve not heard much from Peter Gabriel since his Genesis days. 


  21. This is the reason why, if you are fighting, knocking someone on the the ear is very useful. It helps to make him lose balance. Bar fighting 101. After, it is easier to use simple aikido technique to make him fall and dislocate wrist or shoulder. 

  22. Rajini Rao says:


    Drew Sowersby , sorry to hear that! Any idea what the trigger was..an infection of the ear perhaps? 


    Olivier Malinur , I’ll keep that in mind the next time I end up in a bar fight 😀

  23. Chad Haney says:


    Drew Sowersby my mom had that happen twice (if I remember right). She said it was scary and horrible. The docs couldn’t figure out the cause. So I’m sorry to hear that you experienced that.

  24. Rajini Rao says:


    From what I read, a prosthetic device that administers an electric impulse to the endolymph could reset the signals and stop vertigo attacks. Not sure how close these devices are to being marketed routinely. It would be great if occasional bouts of vertigo could be treated in a doctor’s office with something like this. 

  25. Azlin Bloor says:


    This article is particularly interesting to me, Rajini, I’ve suffered from vertigo since I was a child & have had a few manoeuvres & all sorts of investigations, to no avail. Sometimes, it’s a simple movement like looking up suddenly that sets it off, it’s bizarre! Perhaps next time, I ought to get someone to punch me on the ear like Olivier Malinur suggests in Bar Fight 101 & see if it helps! Kids & I also enjoyed the jelly fish article!

  26. Rajini Rao says:


    Punching down rising dough is good, but Azlin Bloor ‘s ears off limits! Delighted that you showed the jelly fish story to the kids. The vertigo must be awful to live with 😦


  27. Thanks…and the enemy is high intensity/frequency noise!


  28. There are other methods in bar fight, like throwing the pepper in the eyes…


    Rajini Rao , is there cases when these small stones got stuck in a position ?

  29. Rajini Rao says:


    Olivier Malinur , there is a condition called BPPV (Benign paroxysmal positional vertigo) in which these stones are displaced. It can be corrected by the Epley maneuver: http://en.wikipedia.org/wiki/Epley_maneuver


  30. Thanks… I learned one thing today. Each of your post is very informative.


  31. Almost everybody at one time or another experienced vertigo however we are getting it rather “light”. The way system is designed it will work almost always properly – on Earth. Different story happens in the freefall – simply because weight is not present anymore. Quite a large percentage of sky divers experience disorientation and nausea during freefall but this is nothing in comparison to astronauts.People in space are in continous freefall for days and weeks – about 40% to 50% of them experience “vertigo” to a point of vomiting. Most of them will get used to “conflicting signals” in two or three days but not all ( keep it secret – vomiting hero astronaut isn’t picture we would like to see or hear about ;] ).


    The number (40%-50%) is so small because of tests conducted on the Earth – yet it is still half of the crew incapacitated ( to some degree) for couple of days, which may explain NASA’s interest in workings of our inner ear.


  32. BPPV is no fun. Believe me. Mine spontaneously disappeared after several very unpleasant weeks some years ago. The neurologist who treated me was a very wise old clinician. He said “Let me tell you what we are going to do about this. Nothing. It will heal soon. You just have to be patient and avoid violent head motions.” I asked him about Epley maneuvers. “Sure, do it if you like. But it’s complete nonsense. Its only function is making people feel like they are doing something useful. They aren’t.” 

  33. Rajini Rao says:


    Leszek Dziędziewicki , your comment made me look up space vertigo and I found a scary story of how one of the thrusters failed on Gemini VIII causing severe, near incapacitating vertigo to the two astronauts on board (Neil Armstrong and David Scott). The abstract of the paper says:”A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts.” Fortunately, Armstrong accurately diagnosed the problem and took immediate corrective action. NASA has apparently corrected the thruster wiring, whatever that means, so this does not happen again :O


    http://www.ncbi.nlm.nih.gov/pubmed/2302130

  34. Rajini Rao says:


    Joseph M. glad to hear that the problem resolved. On another share of this post, someone just said how the Epley maneuver fixed his BPPV! 🙂


  35. Rajini Rao thank you for this excellent post. I have no idea if the Epley maneuvers work or not. I am only quoting the wise old neurologist. I think we have to at least entertain the hypothesis that BPPV will, given time, go into spontaneous remission in many cases and that the Epley maneuvers are just a way to pass the time. Like I say, just a hypothesis.

  36. Rajini Rao says:


    I have no idea either, Joseph M. . My info came from Wikipedia. I think the wise old neurologist is a better source than Wiki 🙂


  37. Where you the one posting a few days ago about a study on frogs’ hair? The title was quite shocking, but frogs do in fact have “hair”, the one inside the ears.

  38. Rajini Rao says:


    It was the opening joke of my post on hair cells, Víktor Bautista i Roca : http://goo.gl/lEHKjF


    Is that the one? 


  39. Rajini Rao Yeah, I didn’t remember whose was it.


  40. I enjoyed this post Rajini Rao there are various social & emotional issues related to hearing. While working with some in the hospital I use an ipad to communicate. If they are unable to use the computer there are voice braille translation devices. 

  41. Rajini Rao says:


    I had not thought of the challenges in communication with deaf-blind patients, Cheryl Ann MacDonald . Thanks for that insight.


  42. Rajini Rao On deaf-blind people, try to read the Science-Fiction piece “The persistence of the vision”, I think by Jack Vance. It exists as a short story and as a novel, if I remember right. A touching reading.

  43. Rajini Rao says:


    I found On the persistence of vision by John Varley. Have to look for a safe download. 


  44. it is really nice dear but i couldn’t understand it. i aslo have some problem with my ear membrance it has been destroyed, so what to do?


  45. Rajini Rao I got the initials, at least! 🙂


    I read it about 25 years ago, so that’s not bad.

  46. Mary T says:


    Excellent post Rajini Rao ~ I’ve experienced vertigo once, that was enough!  Fortunately, short and self limiting.


  47. Fantastic post — easy to understand, and I learned a lot. Thanks.


  48. Thanks for this great explanation. Another illuminating post.

  49. Marta Rauch says:


    Rajini Rao thank you for the excellent post!

  50. NV NEO says:


    This is a very nice post. I mean all the participation, pretty good insights by all. Definitely going to try the part of “unblocking” my ears next time I’m on a airplane. Usually I chew gum. But now I can show the person i sit next too how “special” I am.. Lol


  51. Very nice & informative article following how we hear!


  52. Hey reasearch on understanding how to Ears are been able to stabilize whole human body is now used to create a artificial stabilizing system for humanoid robot it really wonderful nature is more advanced than human made technology

  53. Dr. Cassone says:


    Thanks Megan McGrory! I think Rajini Rao has amazing posts! I definitely need to follow and reshare her posts more.

  54. Rajini Rao says:


    Thank you, it is really my pleasure to share my interests with you here on G+. 

  55. Anuradha M says:


    Thanks for sharing this post!

  56. Tom Lee says:


    Yayyy! I’m the one who made the 200th +


    Nice post again Rajini Rao 

  57. Rajini Rao says:


    Hah, you would be special even if you were not the 200th, Tom Lee 🙂 Hope you have been well…things are beyond hectic at work/home fronts and I barely have time to post. 

  58. Tom Lee says:


    I’m in the same mode Rajini Rao things have been pretty hectic. I haven’t been posting much either. Hope things have been cool for you too. 🙂


  59. Hi Rajni ! Very very informative post. Thanks for sharing. Have a nice day.

  60. abdul n.m. says:


    Nature’s gift and human”s negligence….


  61. One more excelent post 😉


  62. Fun thing about that epley manouver is that i just now watched three videos on youtube about how it is done and while all start the same way, the second move is signifficantly different in all three videos and also one says it has to be performed quite quickly and the others say slowly. Seems to me like this isnt realy scientifficly founded.


  63. I won’t to say thank u for this post I have menieres disease and one of the things I fight with is when storms move in to my area I live in sometime it gets to the point that I have to lay down cause of the barometric pressure charges so fast it makes my menieres act up so bad that I’m throwing up and I have to stay in bed until the storms stop we are going on two weeks of storms here in Kansas that I think I’ll never be able to get out of bed but think u for ur post I just wish disability would understand that ppl with menieres do not have control of their lives we can do everything our ears Dr tells us and do more to try to stop having spell like we do but meniers has control we don’t so life is really not happy for us and wen the government won’t help with us being to get our disability like me I’ve Been turn down so many times that I have no health ins and about to loss my apt cause right now geting up moving around isn’t an option so if I had a job I would of lost by now cause I can’t work wen the weather is like this but I just keep praying that God will show Me the way thank u for ur post it gives me hope

  64. Rajini Rao says:


    Dustin McAuley I’m sorry that you have Menier’s and wish you better luck ahead in getting help and treatment. Take care. 


  65. Hello people i also have miniere disease for 10years now,i feel dizzy 24hours a day ,i cant walk straight and at night its even worse. Almost all of my family has it and we got all the same problems verry bad hearing an a terrible sound i our head ,you never get juse to it ,if the weather chaches then i can feel it already, i have made a collection about it so take a look follow and write about it .its always fine to see what other people do about it or share some words together ,and its good to get more information about it THANK YOU ALL


  66. Thanks..very informative…

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