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Please can someone clarify why the apex of the lung is considered overventilated even though it has least ventilation?
Physio doubt
- Thread starter rose82
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So, the lungs are suspended off the trachea/bronchi. In doing so, the top of the lungs, the apex, are more stretched then the bottom of the lungs. So, since the lungs and alveoli are more stretched in the top of the lungs, yes they get more air to them, but they are already expanded and can not further expand. Therefore they, themselves, do not ventilate.
or thats my understanding of it...correct me if im wrong. i read that a lot too.
or thats my understanding of it...correct me if im wrong. i read that a lot too.
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thank you for adding your inputs.It is said that as apex is defying gravity,resistance increases,blood flow is less plus your explanation amounts to the fact that it has least ventilation.But again it is said that apex can be considered as over ventilated region..which is confusing??
I think it is because there is more gas exchange at the apex of lung.
I mean V/Q ratio is higher at the apex..because the regional differences for ventilation(V) are not as great as for perfusion(Q)
correct me if im wrong~[/~
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I wud say it is because of the V/Q ratio..though the base recieves the highest amount of blood flow[co2] it is underventilated because it does not have adequate ventlation[o2] and so the ratio of v/Q is less than one making it underventilated..on the contrary the opposite is true for apex where it has least amount of blood flow but the ventilation is more compared to it making the ratio more than one and apex is therefor over ventilated..
I hope this clears the doubt..cheers
I hope this clears the doubt..cheers
