Pulm Physiology Flashcards
TLC is the sum of what 4 volumes?
RV + ERV +IRV + TV
What are the qualitative & quantitative definitions of Vital Capacity (VC)?
amount of air that can be expelled following maximum inhalation; TV + ERV + IRV
What are the qualitative & quantitative definitions of FRC?
Amount of air remaining at the end of a normal expiration; RV + ERV
In obstructive lung diseases such as asthma, bronchitis, & emphysema, how is the Forced Expiratory volume affected?
obstruction will decrease the amount of volume that can be exhaled b/c resistance is increased; so FEV will be reduced with a consequential increase in RV
What is happening to the lung tissue in restrictive lung diseases like pulmonary edema, pulmonary fibrosis & pneumonia?
Lung compliance is reduced and the tissue becomes more stiff; this limits the lung’s ability to expand
How does Restrictive lung disease affect expiratory capacity?
It increases which will cause FEV to increase with a decrease in RV; however, expiration is limited so FVC will decrease
Why does Obstructive Lung disease cause an increase in the FRC?
B/c in obstructive disease, there is air trapping which means more air is going to be left in the lungs after expiration; remember FRC is the maximum expiratory volume following normal inhalation
Why does obstructive lung disease cause a decrease in FVC?
In obstructive lung disease, there is an increase in airway resistance making it more difficult to inhale; this will decrease FVC b/c remember FVC is the maximum amount of volume that can be exhaled following maximum inhalation; if the latter is reduced so will the FVC
How can dead space be calculated?
Using Gohr’s Equation; Dead space = (PaCO2 -PeCO2)/PaCO2
What is the equation for Pulmonary Ventilation?
TV x RR
What is the equation for Alveolar ventilation?
(VT - VD) x RR
What muscle/muscle groups are involved during normal inspiration?
Diaphragm, External intercostals, SCM
What muscles/muscle groups in inhalation become involved when MV > 50
Anterior serratus, Scaleni
What muscles become involved with inhalation when MV > 100?
Spinal erectors, trapezium, posterior neck muscles
The Internal intercostals get involved in expiration past certain passive thresholds; which muscle groups become involved when MV > 40?
Abdominals & Posterior serrati
If the lungs have reduced capability to increase alveolar pressure, which is the cause in OLD, how will this affect the respiration cycle?
Exhalation will be greatly reduced causing more air to stay in the thoracic cavity
If the lungs have reduced capability to decrease alveolar pressure, which is the case in RLD, how will this affect the respiration cycle?
In RLD, the lungs have reduced expansion ability which going to reduce the inspiratory capacity; If IC is reduced, then there is not going to be as much to exhale
