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Larynx model

Introduction
Public summary: 

A working model of the larynx which uses a hand pump to force air across two closely-apposed rubber sheets (i.e. vocal cords) to make a sound.

Functional model of the larynx
Useful information
Kit List: 

Model of the larynx
Laminated endoscopy images of vocal cords and pathologies.
We also have a plastic medical model of the larynx, which can be used in conjunction with the functional model.

Packing Away: 

Lives in a flat grey medical models box (you need to tie the pump shut to fit it in, there should be a loop of string appropriate for this in the box with it).

Frequency of use: 
2
Explanation
Explanation: 

ACTIVITIES:

- use the model to generate different pitches/ how do get low/ high tones (ensure the children are gentle with the model - they usually want to hit the pump as hard as possible to make a loud noise, but this will break it and you can't change the tone unless you press the pump gently).
- use the pictures to illustrate how the larynx works + things that can go wrong with it...
- get the kids to feel their own thyroid cartilage/hyoid bones (could show Adam’s apple if they are accompanied by an older male sibling/their fathers)

THINGS TO TALK ABOUT:

- What is the larynx? Where is it? What does it do?
- How do we generate high/ low pitch (use model)
- Things that can go wrong (cancer, polyps etc.)

BASIC PROCEDURE AND EXPLANATION:

What is the larynx/ voicebox and where is it?

- Get the kids orientated- let them feel their own thyroid cartilage + use the pictures- so the voicebox is the entry to the airways (You could also show them the Adam’s apple if they are accompanied by an older male sibling/ their father)
- What is it made off? Well, it’s hard when you feel it, so it’s made out of something similar to bone... Do they know anything besides bone that is hard? Cartilage...
- However, cartilage is not the only thing that makes up your voicebox- also contains muscles, membranes, mucous membranes... (For older kids, use the anatomical pictures to illustrate this, but don’t go into details...)
- So on top of the larynx sits the epiglottis- it acts like a “lid”, closes when you swallow to protect the airways – Why is this important? Ask them what happens when they eat and talk at the same time- you “mis-swallow” and have to cough - don’t want food to get into airways; vocal cords can also close to protect the airway
- So is the larynx always closed? No, of course not- it needs to be open so that the air can get into the lungs (that is why you have cartilage- it’s a strong material, it helps to keep the entry to the airways open!)

What are the vocal cords and how do they function?

- Use the model to generate different pitches (The kids should really enjoy this), try to get them to figure out what they have to do to get a higher or lower pitch (i.e. do the vocal cords get longer or shorter for higher pitches? )
- so this is how our vocal cords generate sounds- cartilage is moved by muscles (i.e you use your hands (“muscles”) to move the plastic bits (“cartilage”) to lengthen/ shorten the yellow balloon bits (“vocal cords”))
- What else do you need? Air!!!! This is what the pump is for! Show them that it does’nt work if you don’t use the pump
- So when we breath out, air travels from the lungs through the wind pipe and gets to the vocal cords- they can then vibrate and this generates sound
- Do we need anything else for speech? Talk about pharynx, tongues, mouth, teeth, lips, i.e. they all help to “shape sound”

OTHER THINGS TO TALK ABOUT:

- Things that can go wrong: use the pictures- can they find anything that looks funny? Talk about cancer, polyps. What causes them? Cigarette smoke!!! (Your larynx is pretty much the first thing that is exposed to cigarette smoke...)

Another approach:
I was running this model alongside the lung model, so after asking them why you need to breathe (it appears that quite a lot of the general public believe we can extract carbon dioxide from the atmosphere......) I then asked them to try to talk without breathing out, and used that to introduce the idea that breathing out enables us to talk. I got them to put their hands on their throats and hum, then asked if they could feel anything, and explained that the buzzing was their 'voice box' and vocal cords. I then showed them the model, using the lung model to orient it, and explained that in place of bits of balloon we have flaps of 'skin'/membrane in our throats, and that when we speak we force air up between them. I then let the kids play around making noises with the model, getting them to work out how to change the pitch/volume etc. Finally I tried to relate this to how we make sounds by asking them to talk to me without moving their lips or their tongue - the sounds they made were very similar to the 'honking' of the model, so I could explain that the actual sound and how high or low it is is produced by the 'voice box' , but to form words we use our mouth/teeth/tongue/lips/etc. The sound of the model is also quite similar to babies crying, which again is noise made without fine control of the mouth etc.

Risk Assessment
Date risk assesment last checked: 
Fri, 25/01/2019
Risk assesment checked by: 
Matt Worssam
Date risk assesment double checked: 
Sun, 03/02/2019
Risk assesment double-checked by: 
Esmae
Risk Assessment: 

Larynx models: standard medical model and additional functional model.

Hazard Risk Likelihood Severity Overall Mitigation Likelihood Severity Overall
Small parts Risk of swallowing. 2 4 8 Close experiment immediately if small pieces become detached (it won't work then anyway). Do not let children play with experiments unattended. Advise parents to take child to A+E if an item is swallowed. 1 4 4
Broken parts If broken parts could be sharp – risk of cuts. 2 3 6 If model breaks, close experiment immediately and remove broken models. Call a first aider in the event of accident. 1 3 3
Moving parts The functional larynx model has moving parts, in particular the narrower end of the air pump is a finger pinch hazard. 4 1 4 Reduce the finger-pinch hazard by ensuring the pump is placed on a flat surface (table/floor) and only allowing children to press the pump gently with the hands. Ensure fingers are free from the narrow end of the pump and do not let children hold the pump with both hands.
In case of injury, call a first aider.
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Images
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