The Cave of the Ear

“Wow, Mr. Burp! Another learning adventure? We have our cave exploring equipment ready to go. The spelunking gear is ready!”, said Jon.

“Yes, today, away we go into the ear and look at how it works!”, said Mr. Burp.”Is everyone attached to your tethers? We don’t want to lose anybody.”

“Yes Mr. Burp!” the group said.

“We will start with the auricle. The outer ear that directs sound. Headlights on as we go deep into the ear!” whispered Mr. Burp.

“Hey! There’s this sticky, slippery stuff on the bottom! I can hardly keep from falling!”, cried Lisa.

“That’s cerumen or what you call ear wax. It keeps insects and dirt from collecting on the eardrum or the tympanic membrane.”, explained Mr. Burp.

“There’s hair all around here on the top, the walls and the bottom. It’s like walking through a carwash!” said Jon.

“The hair helps push the wax and dirt out of the ear canal.”, said Mr. Burp.”Sometimes it builds up and needs a doctor to help move it out, Wan”.

“That is the tympanic membrane, also known as the eardrum. See it move as we talk?, asked Mr. Burp.

“What’s that on the other side of it?”,asked Jon.

“That is what is called the middle ear. We will explore further. Normally we would not be able to pass through the tympanic membrane, but we will today. Step through this hole.”, said Mr. Burp.

“When the tympanic membrane vibrates or shakes, it makes the three bones of the middle ear move. The bone next to tympanic membrane is the malleus or hammer, which strikes the incus or anvil which shakes the stapes or stirrup. The stirrup vibrates the hairs in the vestibule of the cochlea.”, said Mr. Burp.

“That big snail looking thing is the cochlea?”, asked Lisa.

“Yes.”, said Mr. Burp.”The cochlea is the beginning of the inner ear. There are many hairs in the liquid inside the cochlea that move the auditory nerve which goes to the brain and is recognized as sound.”

“What’s that big tunnel at the bottom of the middle ear under the bones?”, asked Mateo.

“That is called the eustachian (you-stay-shun) tube. It keeps the middle ear dry and maintains the air pressure so that the tympanic membrane and the bones of the ear vibrate without any problems.”, said Mr.Burp.

“Where does it end?”, asked Wan.

“Well, this is how we will leave, so let’s find out!”, said Mr. Burp. “Hold on to your tethers as we slowly descend! When you yawn, this tube opens to let a small amount of air in. It’s that “pop” you hear when flying on an airplane. The air it lets in keeps the middle ear bones dry and keeps the tympanic membrane from rupturing.”

“Weeeeee!”, said Lisa. “That was a straight drop with no curves.”

“Correction. That was a slightly slanted drop without curves.”, said Mr. Burp.

“We are in the mouth!”, said Jon.

“What happens when someone can’t hear?”, asked Mateo.

“It can have three causes or a mixture,” explained Mr. Burp. “The tympanic membrane can be torn as it was when we entered the middle ear, or the bones can become gooey and sticky and won’t vibrate.This is what happens with a cold, allergies or an ear infection. They also will not vibrate if they are under water. This usually happens with allergies or a torn tympanic membrane.”

“If the nerve is damaged,which can be from a virus, medications, or head injury, then the sound is still not transferred to the brain and sometimes there may be a combination of all three!”, stated Mr. Burp.

“Wow! You almost have to be a mechanic to repair the ear!”, said Jon.

“I guess that’s what you would call the doctor that works on the ear. The doctor for the ear is called an otolaryngologist (Oh-toe-laren-goll-oh-jest). Commonly known as the ear-nose and throat doctor.” said Mr. Burp. “They don’t like it when you put things in the ear canal. It is hard to retrieve them when they get stuck and they can cause a lot of damage to the ear by punching holes in the tympanic membrane and breaking the bones of the middle ear. It is not easy to make those repairs. There are very few replacement parts.”

“So we should take care of our ears like we take care of our cars.”, said Lisa.

“Yes.”, said Mr. Burp. “ We need to also keep them protected from loud noises. It damages the hairs in the cochlea. You don’t want to have to use hearing aids before you are 30 years old.”

“Well, this ends today’s adventure. Get ready for the next one, gang!”, said Mr. Burp. “Goodbye!”

“Goodbye Mr. Burp!”, said the gang.”See you next time!”

References

http://www.asha.org
http://www.mayoclinic.org
http://www.healthyhearing.com

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