cardiac output to lungs

[lattimer13]

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so on pg 146 of BRS physiology it says 2% of CO bypasses the lungs.

so maybe i've forgotten my cardiopulmonary anatomy, but i thought all CO traversed the lungs. what accounts for the 2%?

 

[eurotrash]

Probably a reference to the slight V/Q mismatch that happen even in normal lungs, or the L-to-R shunting which occurs via thebesian veins/coronary arteries in the heart.

I dont think tha tthis is a reference to the bronchial arteries as the blood in them does pass through the lungs prior to reaching the lungs again.

Let me know what you think.

 

[StringBean]

The 2% goes to feed the nonrespiratory conducting tissues of the lungs & viseral pleura via the bronchial arteries. They arise from the thoracia aorta (1 for the right & 2 for the left lung). 🙂

Hope that helped!

~Bean

 

[Idiopathic]

Yes, the bronchial circulation is the cause of most of the shunt.

 

[Mossjoh]

There is some communication between the pulmonary veins and bronchial veins so that a little blood mixes between them...

 

[lattimer13]

Probably a reference to the slight V/Q mismatch that happen even in normal lungs, or the L-to-R shunting which occurs via thebesian veins/coronary arteries in the heart.

I dont think tha tthis is a reference to the bronchial arteries as the blood in them does pass through the lungs prior to reaching the lungs again.

Let me know what you think.

you're right about the thesbian veins...that's exactly what our respiratory physiology professor said after i emailed him.

you're also correct about the bronchial arteries. way to go!