Airway resistance from mouth to alveolus is 2 cm H2O-sec/liter. [These units are pressure/flow as in cm H2O/(L/s)]. If alveolar pressure is + 10 cm H2O, what is the magnitude and direction of the airflow?
5 L/s expiratory flow, (ref pg. 28 in iBook)
At FRC with relaxed muscles, pleural pressure is -6 cm H2O. If an inspiratory muscle force of 4 cm H2O is suddenly applied and the airway resistance is 2 cm H2O-s/L, what is the immediate airflow?
2 L/s (ref pgs. 23 and 28 in iBook).
In normal, resting conditions, expiration requires the activation of expiratory muscles. (T/F)
False. (ref pg. 24 in iBook)
In the P-V plot shown, the red-shaded area is:
- energy required to overcome the airway resistance.
- energy of inspiration turned in to heat or otherwise lost.
- energy stored in the gas that has been inspired,
- energy that has been stored in the elastic structures of the chestwall.
energy that has been stored in the elastic structures of the lung and chestwall.
Option 5 is correct. (ref pg. 27 in iBook)
The larynx is a site of high resistance to airflow in the conducting airway path (T/F).
True. (ref pg. 28 in iBook)
In normal subjects, peak inspiratory airflow in wakefulness is limited only by the peak inspiratory effort (T/F).
True. (airway resistance is not increased by a maximal effort: ref pgs. 31 in iBook)
In normal subjects, peak expiratory airflow is limited only by the peak expiratory effort (T/F).
False. (ref pg. 32 in iBook)
Expiratory flow limitation increases as lung volume _______________.
decreases. (ref pgs. 33 in iBook)
The maximum volume contained in the lung is the _______________.
Total lung capacity (TLC). (ref pg. 33-4 in iBook)
The largest tidal volume that can be inspired is called the ________________.
Vital capacity (VC). (ref pg. 33-4 in iBook)
The residual volume (RV) is the __________________.
Smallest lung volume that can be achieved with maximal expiratory effort. (ref pg. 33-4 in iBook).
Typically, FRC is about 2 liters and the residual volume is only a few hundred ml (T/F).
False- the FRC is about 2 liters, but the RV is only about 0.5-1 liter less (ref pg. 33 in iBook).
Expiratory airflow limitation per se is a marker for airway disease. (T/F)
False. (iBook pg. 32.)