Step I Where does cilia end in respiratory tract?

[anbuitachi]

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First aid says it ends in terminal bronchiole.. one of my uworld quesitons say resp bronchiole and another says terminal bronchiole.. confused.

Also since goblet/mucus secreting cells end in bronchi... what are these cilia beating up if there is no mucus to beat?

 

[sharklasers]

I would say to the terminal bronchioles. They would probably beat up any residue mucus that might make it past the bronchi.

 

[Goober11]

I would say to the terminal bronchioles. They would probably beat up any residue mucus that might make it past the bronchi.

I know this is nitpicky and correct me if I am wrong, but aren't there cilia THROUGH the terminal bronchioles stopping before the respiratory bronchioles?

 

[Sanzy]

It's up to the respiratory bronchioles. FA says that columnar ciliated cells extend up to the terminal bronchiole. Cuboidal ciliated cells continue up to the respiratory bronchiole.

 

[sharklasers]

I know this is nitpicky and correct me if I am wrong, but aren't there cilia THROUGH the terminal bronchioles stopping before the respiratory bronchioles?

Yeah you are right, I just worded that poorly, my bad!

 

[223556]

I have in my notes that cilia even goes further into the respiratory bronchioles. Am I wrong? I think it came from a UWorld explanation.

Anything "bronch-" = cilia. <-- What I have written down.


It actually would make sense NOT to have cilia in the respiratory bronchioles since they are epithelial cells that can participate in gas exchange right?

 

[Sanzy]

I think you're right. Cuboidal ciliated cells are found in the respiratory bronchioles along with some alveoli in the walls.

 

[voicesinmyhead]

Bump. So if question asks, till where is cilia found, it should still be respiratory bronchiole?

Wonder why would uworld give conflicting explanations.

 

[worldbeater]

From what I have read, cilia lines the entire airway, so that means through the terminal bronchiole and respiratory bronchiole. May differ from what others think.

 

[worldbeater]

So here is something I wrote down in my Notes from an incorrect UWorld question: "cilia is the last to disappear"..and then what is printed in the Notes says "cilia is present all the way down to the alveoli"

From this, that means the cilia has to reach deep down all the way to the alveolus, which means in sequence it lines terminal bronchiole -> respiratory bronchiole -> alveolar duct -> alveoli

This would make sense, because the respiratory unit (respiratory bronchiole->->alveoli) is where all the large sized o2 molecule exchange occurs, you want to keep it as clean as possible to allow diffusion of o2 into the vasculature

I know this is a tricky topic, that's why they like to ask questions on it, FA can be vague sometimes.

 

[walakin25]

so to answer this question im gonna reference how particulates (i.e. dust) are cleared depending on size. larger particles 10-15um and greater are trapped in URT and coughed out. 2-10 um in size enter trachea/bronchi and are cleared via mucociliary clearance (cilia run till resp broncioles and terminate here), resp bronchioles are simple ciliated cuboidal epithelium. less than 2 um reach alveoli and are eaten by macrophages.

 

[Pegahkhz]

dear friends, does respiratory bronchioles have cilia?