episode39

039 The Function of the Organ of Corti

The organ of corti – such a small part of the cochlea with such a major function. Watch as Leslie demonstrates how the vibrations in the cochlea affect the cilia on the hair cells, and how this process is translated to hearing.

There’s also a really cool video of a hair cell dancing to Rock Music.

Enjoy!

Transcript of Today’s Episode

Hello, and welcome to another episode of Interactive Biology TV, where we’re making biology fun! My name is Leslie Samuel and in this episode, Episode 39, I’m going to be talking about the function of the Organ of Corti. And don’t worry, I won’t be singing in this episode. That’s Episode 38. So, if you want to hear me sing, go to Episode 38 and enjoy! Today, we are just going to talk about the function of the Organ of Corti. So let’s get right into it!

Now, we’ve been looking at this picture and we’ve been looking at the structure of the ear. We look at the fact that sound waves come in here; cause vibration in the tympanic membrane; causing the malleus, incus, and stapes to vibrate; and then causing the fluid inside of the cochlea to vibrate. In the last episode, we unrolled the cochlea and we looked at it like this. And we showed that, depending on where it vibrates, that’s going to send signals to the brain, and the brain can interpret that as a certain pitch, a certain frequency.

Now, there are a few things that I want you to pay attention to in this episode that we did not pay attention to in the previous episodes. And that would be here. We have the scala vestibuli. That’s this cavity at the top here. And below the basilar membrane, we have the scala tympani. And that’s the cavity at the bottom of the cochlea, beneath the basilar membrane.

And what I’m going to do in the next picture is, I’m going to actually take a cross-section. So I’m going to cut straight through the cochlea like this, and we are going to look at a cross- section of the cochlea. So let’s go to the next figure.

Here, we are looking at the cross-section of the cochlea. And here, you can see we have the scala vestibuli. And here we have the scala tympani. And here, this is the basilar membrane. And right above the basilar membrane, we have the Organ of Corti. So that’s this section right here. We can’t see too many details about it, but that is the Organ of Corti. Here we can see more details. This entire structure is the Organ of Corti.

But I just want you to pay attention to how it is laid out here, with the Organ of Corti here, scala vestibuli at the top. This is the basilar membrane. And here we have the scala tympani. One more place that I want you to pay attention to, here, is another cavity we call the cochlear duct. And once again, in here we have the Organ of Corti. So this is a cross-section of the cochlea, and that’s how it’s laid out.

Now, I want to bring your attention to the Organ of Corti which is shown clearly right here. Once again, we can see here we have the basilar membrane, and on top of that we have the Organ of Corti. A few more things to point out here. This membrane here, it says membrana tectoria. We call this the tectorial membrane.

And we look at the fact that, when sound enters the cochlea, that causes the basilar membrane to vibrate up-and-down. Now, when that vibrates up-and-down, that’s going to cause the Organ of Corti to move up and down. Then, here we have the tectorial membrane that’s attached only at one end. So, as the basilar membrane is going up-and-down and the Organ of Corti is going up-and-down, that is going to cause the tectorial membrane to move in a windshield- wiper-like fashion. So it’s just going to flap like a windshield wiper.

Now, in the Organ of Corti, we have a number of different hair cells. We have inner hair cells, which would be this one here; and we have outer hair cells, which would be these four here. Now, as you can imagine, if the entire Organ of Corti is moving up-and-down, the tectorial membrane is moving in a windshield-wiper-like fashion, that tectorial membrane is going to cause this outer part of the hair cells to vibrate. And these outer parts are called cilia. So, it’s going to cause the cilia to bend. And that’s the process that’s going to cause a signal to go via the auditory nerve to the brain.

Now, there is a very important thing to understand here. The part that responds to the tectorial membrane that is directly responsible for hearing would be the inner hair cells. And that sends a signal to the brain. However, the outer hair cells are involved in modulating the response and helping the inner hair cells so that you can hear better.

So once again, when the sound comes into the cochlea, the basilar membrane vibrates up-and-down that causes the tectorial membrane to move in a windshield-wiper-like fashion, causing the cilia and the hair cells to bend. And when the cilia and the inner hair cells bend, that causes a signal to be sent to the brain. The outer hair cells are involved in modulating the response to that sound.

Now, I have a very fascinating video to show you that’s going to show what happens to the outer hair cells in response to sound. So sit back, relax, and enjoy the ride!

{Short Video Clip of Outer Hair cell dancing to music}

So, as you can see in a very interesting way, this hair cell was vibrating up-and-down. It was vibrating in response to the sound. And that process is involved in modulating the response to hearing. This causes signals to be sent to the brain and the brain gets a full picture of the sound that you are listening to.

That’s it for this video. If you have any questions, as usual, leave them in the comments section below. And you can always visit the website at Interactive-Biology.com for more Biology videos and other resources. That’s it for now, and I’ll see you in the next one.

129 comments
Abby
Abby

so are the hair cells in the cochlea sort of like neurons?

Samantha Nelson
Samantha Nelson

thank you very much!! you make it more simpler! and now i understand it for my exam that is in 4 hours!

umarg2012
umarg2012

Awesome video watching for my medical professional examinations.

oth4ever32
oth4ever32

Great video, just one suggestion. It would be helpful if the pictures were more clear and bigger, i can barely see the labels.

theewhatever
theewhatever

Human physiology exam after tomorrow: YOU'VE JUST SAVED MY LIFE :D I trully understand everything now, IT'S AMAZING. THANK YOU (I think I've seen almost all your videos since yesterday!)

Matias Monteagudo
Matias Monteagudo

This series of videos are absolutely mind blowing, and how the muscle works too. Who needs science fiction when you can see how complex and amazing are these systems inside our body?. It's all chemistry in action.

Hanna Smith
Hanna Smith

Helped me very much on understanding how hearing works. I have a final today and this just finalized all my studying! Thank you so much. I love the videos! :) Keep em' coming!

phillipoye
phillipoye

I'm wondering about the number of hair cells you mentioned. I've been tough that we got 3 rows of outer hair cells instead of 4. Otherwise great videos. Concerning hearing mechanism, haven't found better that includes so many details. Cheers

phillipoye
phillipoye

I'm wondering about the number of hair cells. I've been tough that we got 3 outer hair cells instead of 4. Otherwise great videos. Concerning hearing mechanism, haven't found better that includes so many details. Cheers

Ashwin
Ashwin

Thanks a lot sir, it really helped me for preparing for my 1st term exams.

Mokimoto00
Mokimoto00

I just want to say thank you very much for these videos. They are well presented and described, and moreover, you have been able to clearly present these facts in 10 minute videos whilst allowing the audience to understand every step. I wish i found your videos earlier! I was never a real fan of biology, but your videos have showed me a new perspective, which makes biology far far FAR more easier to understand as opposed to reading my textbooks. A big THANK YOU to you! Highly appreciated!

pixiesashes
pixiesashes

this is the coolest thing I have ever seen! the dancing hair!

melmelgmckenzie
melmelgmckenzie

In regards to inner & outer hair cells depicted, where 1 is labelled inner & 4 are labelled outer. I noticed that the arrow is pointing to different ends of the hair cells. So is the outer hair cells the part of the cilia that is external and being bent, and the inner hair cells the part of the cilia that is internal. Analogous to the hair outside of our skin and inside of our skin. Or, are the outer and inner hair cells respectively called such because of their positioning along the structure?

melmelgmckenzie
melmelgmckenzie

Hi there, I was wondering, what makes the tectorial membrane move in the window wiper fashion? Is it because it is connected to the Basilar membrane at the very end there?

chillifire
chillifire

Animation plus proper narration = Win (Thank you)

Bucs4Life8
Bucs4Life8

amazing videos helping very much for my sensation and perception psychology final, Thank You

Bucs4Life8
Bucs4Life8

amazing videos helping very much for my sensation and perception psychology final, Thank You

111amolamusica111
111amolamusica111

Fantastically explained. I will come here for more. Thank you!!

111amolamusica111
111amolamusica111

Fantastically explained. I will come here for more. Thank you!!

Babybobgirl
Babybobgirl

:OMg! So am I! exam on monday! This video is very useful, wish my lecturer was as techno savvy...THANK YOU VERY MUCH! = )

Babybobgirl
Babybobgirl

@iRockPink23 :OMg! So am I! exam on monday! This video is very useful, wish my lecturer was as techno savvy...THANK YOU VERY MUCH! = )

Babybobgirl
Babybobgirl

@iRockPink23 :OMg! So am I! exam on monday! This video is very useful, wish my lecturer was as techno savvy...THANK YOU VERY MUCH! = )

Babybobgirl
Babybobgirl

:OMg! So am I! exam on monday! This video is very useful, wish my lecturer was as techno savvy...THANK YOU VERY MUCH! = )

Babybobgirl
Babybobgirl

:OMg! So am I! exam on monday! This video is very useful, wish my lecturer was as techno savvy...THANK YOU VERY MUCH! = )

Joyce
Joyce

Wow! Thank you so much!!! You're explanation is very clear! I love it! (-: Again, thank you. You're explanation helps me a lot! God Bless You

sree9555
sree9555

do you have any videos about semilunar canal , saccule , utricle etc sir??

sree9555
sree9555

do you have any videos about semilunar canal , saccule , utricle etc sir??

sree9555
sree9555

do you have any videos about semilunar canal , saccule , utricle etc sir??

InteractiveBiology
InteractiveBiology

Thank You! Stay tuned for more... WE have more Biology videos coming very soon!

InteractiveBiology
InteractiveBiology

@youremocional The organ of corti play a part in the hearing process...

InteractiveBiology
InteractiveBiology

Thank You! Stay tuned for more... WE have more Biology videos coming very soon!

InteractiveBiology
InteractiveBiology

@iRockPink23 Thank You! Stay tuned for more... WE have more Biology videos coming very soon!

iRockPink23
iRockPink23

Awesome video! Using it to study for my audiology exam

iRockPink23
iRockPink23

Awesome video! Using it to study for my audiology exam

youremocional
youremocional

I Don´t Understand what that video is... It´s funny, but, what it is... a cel??... the tectorial membrane... please, answer my question... Great video ;)

youremocional
youremocional

I Don´t Understand what that video is... It´s funny, but, what it is... a cel??... the tectorial membrane... please, answer my question... Great video ;)

Djalitana
Djalitana

that was great. at this stage I know too little to be able to ask questions. just want to say than you.

Djalitana
Djalitana

that was great. at this stage I know too little to be able to ask questions. just want to say than you.

hayder
hayder

leslie you helped me very much,thank you and i downloaded all your vid,i am greatful to you

Leslie Samuel
Leslie Samuel

You are very much welcome. Glad it's helping!

Lrsamuel
Lrsamuel

I'm gonna be posting a few more for download soon, so stay tuned :)

hayder
hayder

i am sorry,i am grateful to you, not greatful i make a mistake because i was tired and fasting. lol

Lrsamuel
Lrsamuel

Oh, not a problem. We all make mistakes :)

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