Pressure difference holding lungs open
Opposes the elastic recoil of the lung
Chest Wall
Pressure difference holding chest wall in
Opposes elastic recoil of the chest wall
Reticular Network
Trying to get the lung to collapse
Thoracic walls are also like spring loaded mechanisms
Pleurae link the pressures and cause combined pressure-volume curve
Curve between the pressures of the lung and chest wall pressure curve
Lung Volumes
At the end of a normal expiration, if you forcefully exhale, you can drop it to about 1200
mL at most
This is the
expiratory reserve volume
Residual volume –
no matter how hard to try to exhale there will be a large volume of
air still in the lungs
If you forcefully inhale, the difference between that and the normal inhalation is called
the
inspiratory reserve volume
Difference between volume at end of expiration and maximum you can suck in is
inspiratory capacity
Difference between end of expiration and 0 is called
functional residual capacity
Tidal volume –
How much air you breathe in with each breath
Anatomic dead space that does not do gas exchange (150 mL)
Alveolar gas 3000 mL
These are static volumes
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Minute Volume
How much air goes into and out of the lung per minute
mL/min
if you multiply that by breaths/min you get alveolar ventilation
If you want to know how much air moves into and out of dead space, that is the minute
volume

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- Spring '13
- ArthurDunham
- Physiology, fresh air, Alveolus, Pulmonary surfactant, dead space air
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