# Virtual Lung Dissection?



## exodus (Oct 25, 2011)

Does anyone know of one online? I'm trying to learn more in depth the structure of the lungs. I'm pretty confused about where the air actually exits the trachea / bronchioles to fill up the lungs.... If that's even how it works. I want to find out what actually makes the chest rise? Are the lungs sort of like a bag of air and the bronchioles floating inside it with the vessels around the alveloi for gas exchange? Or how does it work? The A&P book doesn't really go into this type of structure and I'm confused.


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## JPINFV (Oct 25, 2011)

exodus said:


> Does anyone know of one online? I'm trying to learn more in depth the structure of the lungs. I'm pretty confused about where the air actually exits the trachea / bronchioles to fill up the lungs....



Conducting airway: Trachea->Bronchi->Bronchiole->

Respiratory airway: Respiratory bronchioles -> Alveolar duct->Alveolar sac-> Alveoli 

Conducting airways do not participate in gas exchange. Respiratory airways do. 



> I want to find out what actually makes the chest rise?



The external intercostals and diaphragm contracts, which increases the diameter of the chest. Due to this, the interthoracic pressure decreases. Assuming an open airway, this means that the air pressure inside the lungs is less than air outside the lungs, which will lead to air moving from outside to inside to equalize the pressure. 




> Are the lungs sort of like a bag of air and the bronchioles floating inside it with the vessels around the alveloi for gas exchange?



More like a sponge on a stick than a bag of air. 

Histologically: 







Type 1 pneumocyte = alveolar walls. 
Type 2 pneumocyte = surfactant factories 
Dust cell = macrophage

Arteries are located inside the walls between the type 1 pneumocytes. So gas has to diffuse across 2 cells (the cell making up the capillary wall and the type 1 pneumocyte)


Or how does it work? The A&P book doesn't really go into this type of structure and I'm confused.[/QUOTE]


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## exodus (Oct 25, 2011)

Okay, so the air never actually leave the respiratory airway, just go through the passages and into the respiratory airway where gas exchanges, and then comes back out?


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## Handsome Robb (Oct 25, 2011)

exodus said:


> Okay, so the air never actually leave the respiratory airway, just go through the passages and into the respiratory airway where gas exchanges, and then comes back out?



Yea basically. "Air" is made up of ~78% nitrogen, 21% O2 and ~1% of other gases ie CO, H2O, Hydrogen, argon, yadda yadda.

Your lungs are responsible for not only oxygenation but also waste expulsion (CO2).

O2 molecules exchange through the alveolar wall into the capillaries through diffusion (high concentration -> low concentration) and CO2 goes the opposite way, also through diffusion. Capillaries -> alveoli then exhaled.


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## JPINFV (Oct 25, 2011)

redacted... reuploading... Grrr


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## mycrofft (Oct 25, 2011)

*More like....*

...broccoli. No, cauliflower.
Yep, muscles begin expansion and 14 lbs/sq inch median ambient sea level air pressure does the rest.


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## JPINFV (Oct 25, 2011)

mycrofft said:


> ...broccoli. No, cauliflower.
> Yep, muscles begin expansion and 14 lbs/sq inch median ambient sea level air pressure does the rest.




Provided no airway obstruction (both normal and otherwise), and provided no change in lung volume, atmospheric pressure and alveolar pressure is the same.


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## JPINFV (Oct 25, 2011)

exodus said:


> If that's even how it works. I want to find out what actually makes the chest rise?


[youtube]http://www.youtube.com/watch?v=SJgO72DkFZg[/youtube]

...and don't talk about my "umms." I did this improv style.


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## exodus (Oct 26, 2011)

That actually made a lot of sense. Thanks.

You should add a few tags and a description so more people would find it on youtube, it was very good.


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## JPINFV (Oct 26, 2011)

Well, it's linked from my blog now too...


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## mycrofft (Oct 26, 2011)

*Don't forget pliance of the tissues.*

We OG's tend to find our bronchioles and alveoli a little stiffer as we get older.
Hey, do one with pneumotyhorax, and haemothorax.
Oh, J, nice watch.


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