Ventilation Flashcards
What is minute ventilation?
Amount of air flowing through the lungs in one minute, as expressed by this formula: tidal volume x respiratory rate
What is alveolar ventilation?
Volume of air in the alveolar space in one minute (usually roughly 4.2 L)
The alveoli represent _____ percent of lung volume.
70
Generally, ventilation is only affected by _______ disease states.
severe
During exercise, ventilation increases ______ fold.
10
Due to gravity, alveoli at the top are _______.
larger (by about 2.5 times)
Smaller alveoli have ________ ventilation.
more
Elastic work is greater at _________.
high tidal volumes
Airway resistance is decreased by ___________.
increased volume
Those with obstructive diseases breathe at _____ frequency and ______ tidal volume.
lower; higher
In the lung, what is dead space?
Areas that do not participate in gas exchange
Physiologic dead space is __________.
the sum of the anatomical dead space and alveolar dead space
How does dead space affect ventilation?
It increases the work of breathing, because less of the air participates in ventilation.
Why is residual capacity decreased in those with pulmonary fibrosis?
Their lungs are more rigid, and thus they pull inwards more than healthy lungs.
What is the formula for rate of airflow?
FEV(1.0) / FVC, which is usually ~0.8
The functional residual capacity represents ___________.
the volume of the lung at the end of expiration during quiet breathing
Large aveoli have _______ compliance.
less
Those with obstructive diseases have more resistance work at ___________.
the same elasticity levels
Differentiate functional residual capacity and reserve volume.
Functional residual capacity is the amount of air in the lungs after a normal, resting expiration, and reserve volume is the amount of air in the lungs after a forced expiration.
Functionally, what does FEV/FVC mean?
It is the amount of air that you can get out of your lungs in one second. Because a normal value is ~0.8, this means an average person can get 80% of their vital capacity out of their lungs in one second.
Of RV, FRC, TLC, VC, and FEV/FVC, which values would be decreased in a person with a restrictive lung disease?
TLC and VC would be most decreased; RV and FRC would also be decreased, but less so. FEV/FVC would be normal or small increase.
Of RV, FRC, TLC, VC, and FEV/FVC, which values would be decreased in a person with bronchitis?
TLC would remain the same. FEV/FVC would be decreased. VC would be decreased. RV and FRC would be increased.
Minute ventilation is always ________ alveolar ventilation.
greater than
For many milder diseases, ventilation is often ____________.
regionally compensated
Larger alveoli will have _________ ventilation. Why?
less; think of the pressure-volume plot–there is less compliance at higher volumes
Someone whose primary problem is increased airway resistance would want to breathe at _________.
larger tidal volumes
A typical value for Vt is ________.
500 mL
The maximum volume of air forcefully expired after a maximal inhalation is called ______.
vital capacity
Unlike the other obstructive diseases, emphysema can cause ___________ vital capacity.
unchanged or increased
