Question 1

Maximal expiratory flow rates decrease during exhalation (i.e.,in going from higher to lower lung volumes)for the following reasons:&#10;A)Intra-airway pressures increase and elastic recoil pressure increases at lower lung volumes.&#10;B)Intra-airway pressures decrease and elastic recoil pressure increases at lower lung volumes.&#10;C)Intra-airway pressures increase and elastic recoil pressure decreases at lower lung volumes.&#10;D)Intra-airway pressures decrease and elastic recoil pressure decreases at lower lung volumes.&#10;E)There is no change in intra-airway pressures or elastic recoil pressures at lower lung volumes.

Accepted Answer

Maximal expiratory flow rates decrease during exhalation primarily because intra-airway pressures decrease and elastic recoil pressure decreases at lower lung volumes. This reduction in pressures makes it harder to expel air quickly.

Question 2

Which of the following diseases is associated with concaveness of the expiratory flow volume curve?&#10;A)Cystic fibrosis&#10;B)Pulmonary fibrosis&#10;C)Duchenne's muscular dystrophy&#10;D)Scoliosis&#10;E)Paralysis of the diaphragm

Accepted Answer

Cystic fibrosis is associated with concaveness of the expiratory flow volume curve due to airway obstruction.

Question 3

Air trapping is a sign of premature airway closure and results in:&#10;A)Movement of the equal pressure point at low lung volumes into the intrathoracic airways.&#10;B)Movement of the equal pressure point at low lung volumes toward the alveolus.&#10;C)Movement of the equal pressure point at low lung volumes toward the mouth.&#10;D)No effect on the location of the equal pressure at low lung volumes.&#10;E)Movement of the equal pressure point from airways with cartilage to airways without cartilage.

Accepted Answer

Air trapping, indicative of premature airway closure, causes the equal pressure point (the point along the airways where the pressure inside the airway equals the pressure outside the airway) to move toward the mouth at low lung volumes. This is because the increased resistance in the peripheral airways prevents normal airflow, leading to a shift in the equal pressure point.

Question 4

Common pulmonary function abnormalities in individuals with moderate obstructive pulmonary disease include: A)Normal forced expiratory volume in 1 minute (FEV₁),normal expiratory flow rates,normal ratio of residual volume (RV)to total lung capacity (TLC) B)Increased FEV₁,increased expiratory flow rates,increased RV/TLC ratio C)Decreased FEV₁,decreased expiratory flow rates,increased RV/TLC ratio D)Decreased FEV₁,decreased expiratory flow rates,decreased RV/TLC ratio E)Decreased FEV₁,normal expiratory flow rates,increased RV/TLC ratio

Accepted Answer

Individuals with moderate obstructive pulmonary disease typically have decreased FEV1, decreased expiratory flow rates, and an increased RV/TLC ratio due to air trapping in the lungs. Option A and B describe normal or increased values, which are not typically seen in individuals with moderate obstructive pulmonary disease. Option D describes a decreased RV/TLC ratio, which would be more consistent with restrictive lung disease. Option E describes a decreased FEV1 but normal expiratory flow rates, which is not typical of obstructive pulmonary disease.

Question 5

The flow resistance across a set of airways is lowest under which of the following conditions?&#10;A)Airway radius is large and airways are in series.&#10;B)Airway radius is large and airways are in parallel.&#10;C)Airway radius is small and airways are in series.&#10;D)Airway radius is small and airways are in parallel.

Accepted Answer

The flow resistance across a set of airways is inversely proportional to the fourth power of their radius. Therefore, larger airway radius will result in lower resistance. When airways are in parallel, the total flow resistance is lower than when they are in series. Therefore, option B (large airway radius and in parallel) has the lowest flow resistance.

Question 6

Which of the following factors is not associated with an increase in work of breathing?&#10;A)An increase in tidal volume&#10;B)An increase in respiratory rate&#10;C)Diseases associated with airway obstruction&#10;D)Diseases associated with loss of lung compliance&#10;E)None of the above

Accepted Answer

All the options listed (A-D) are associated with an increase in the work of breathing, making E the correct choice as it states none of the options are exceptions.

Question 7

The airways most responsible for the resistance of the respiratory system (R_aw)during mouth breathing are: A)The trachea,main stem,and lobar bronchi. B)The terminal bronchioles. C)The respiratory bronchioles. D)The alveoli and alveolar ducts.

Accepted Answer

The trachea, main stem bronchi, and lobar bronchi have larger diameters and therefore offer less resistance to airflow compared to smaller airways such as the terminal bronchioles, respiratory bronchioles, alveoli, and alveolar ducts. This means that during mouth breathing where airflow is unimpeded by nasal structures, the larger airways are the most responsible for the resistance of the respiratory system.

Question 8

Factors associated with higher expiratory flow rates include:&#10;A)Low lung volume.&#10;B)Increased lung elastic recoil.&#10;C)Negative pleural pressure.&#10;D)Increased pulmonary vascular resistance.&#10;E)None of the above.

Accepted Answer

Increased lung elastic recoil is associated with higher expiratory flow rates because it allows the airways to remain more open during expiration, enabling more efficient airflow. Low lung volume (A) can limit expiratory flow rates as the airways may collapse due to decreased supportive appositional forces from lung parenchyma. Negative pleural pressure (C) can aid in inspiration, but has no direct impact on expiratory flow rates. Increased pulmonary vascular resistance (D) refers to resistance within the blood vessels, not the airways, and is not associated with expiratory flow rates.

Question 9

Pulmonary fibrosis is associated with a decrease in lung compliance.Individuals with pulmonary fibrosis:&#10;A)Have a higher airway resistance than do individuals with normal lungs.&#10;B)Require a higher transpulmonary (translung)pressure for a change in lung volume than do individuals with normal lungs.&#10;C)Have a shift in their oxyhemoglobin dissociation curve to the right.&#10;D)Have an increase in dead space.

Accepted Answer

Pulmonary fibrosis results in increased stiffness of the lungs, which causes a decrease in lung compliance. This means that a higher transpulmonary (translung) pressure is required to achieve the same change in lung volume as compared to individuals with normal lungs. Option A is incorrect because airway resistance is not directly affected by pulmonary fibrosis. Option C is also incorrect because there is no evidence that pulmonary fibrosis leads to a shift in the oxyhemoglobin dissociation curve. Option D is also incorrect because pulmonary fibrosis does not cause an increase in dead space.

Question 10

Common pulmonary function abnormalities in individuals with moderate restrictive lung disease include: A)Normal FEV₁,normal expiratory flow rates,and normal RV/TLC ratio. B)Increased FEV₁,increased expiratory flow rates,and increased RV/TLC ratio. C)Decreased FEV₁,decreased expiratory flow rates,and increased RV/TLC ratio. D)Decreased FEV₁,decreased expiratory flow rates,and decreased RV/TLC ratio. E)Decreased FEV₁,normal expiratory flow rates,and increased RV/TLC ratio.

Accepted Answer

In moderate restrictive lung disease, pulmonary function tests typically show a decreased Forced Vital Capacity (FVC), which may lead to a decreased FEV1 (Forced Expiratory Volume in 1 second) if the reduction in lung volume is significant. However, because the disease primarily affects lung volume and not the airways, expiratory flow rates can remain normal. The RV/TLC (Residual Volume/Total Lung Capacity) ratio is often increased due to the decreased compliance of the lung or chest wall, making it harder to fully expel air, thus increasing the proportion of air remaining in the lungs (RV) relative to the maximum amount of air the lungs can hold (TLC).

Deck 22: Dynamic Lung and Chest Wall Mechanics