Dynamic Airway Flashcards
1
Q
What is the Z pressure point?
A
- the point where transmural pressure pressure across the airway is zero
2
Q
what happens when the transmural pressure gradient is negative
A
- intrapleural pressure exceeds internal airway pressure
- airways may collapse
3
Q
where is Z located during the effort dependent phase of forced expiration?
what happens?
A
- within the cartilaginous airways
- prevents it from collapsing due to negative transmural pressure gradient
4
Q
where is Z located during the effort independent phase of forced expiration?
what happens?
A
- Z point is within the non cartilaginous airways now
- negative transmural pressure gradient causes airway to collapse
- expiration driven by elastic recoil
5
Q
air flow during effort dependent phase of forced expiration
A
- air flows outward under force of elastic recoil and enhanced by elevation in intrapleural pressure
6
Q
elastic recoil in emphysema
A
- lower elastic recoil
7
Q
airway resistance in emphysema
A
- high airway resistance
8
Q
expiratory flow rate in emphysema
A
- low expiratory flow rate
9
Q
what is the FEV1/FVC ratio
A
- how fast you can get volume out compared to overall volume.
