True/False: a spirometry is able to measure the total lung capacity
False, spirometry is not able to measure residual volume, therefore it is only capable to measure vital capacity
How is residual volume measured?
Using gas dilutional technique
What is gas dilutional technique?
Inhaling Helium so to equilibrate throughout the lungs and chamber
Which equation is used to measure residual volume?
C1V1= C2V2
V2= total lung capacity + initial volume
What is minute ventilation?
Volume of air that moves into and out of the lungs per minute
How fast air in lungs get replaced
What is alveolar ventilation?
It is minute ventilation minus dead space
How fast air in the alveoli get replaced
Which equation is used to calculated minute ventilation (Ve)?
VE= Tidal volume x respiratory rate
Which equation is used to calculated alveolar ventilation (Va)?
Va= (Vt-Vd) x RR
(Tidal volume – dead space) x respiratory rate
Exhaled breath includes air that ____ and ______.
Participated in gas exchange; did not participate in gas exchange
Is it possible to have exhaled gas concentration be totally equal to alveolar gas concentration?
No way José. There is definitely dead space because of conducting zone, and air in there do get exhaled out along with alveolar exhaled gas
More dead space, more _____ the exhaled breath is.
Dilute. Because of less pCO2 (reduced partial pressure of CO2)
True/False: dead space air does not have any CO2
True
How would you calculate the dead space pCO2?
Bohr equation:
Vd= [(Arterial pCO2- exhaled pCO2) / arterial pCO2] x Vt
Arterial pCO2 value is used to estimate which other volume?
Alveolar pCO2
What dos the Bohr equation tell us?
Fraction of tidal volume that remained in the dead space
What is Boyle’s Law?
P1V1= P2V2
What does Boyles Law tell us?
Pressure of a gas is inversely related to the volume of the gas
Air flow is ______ proportional to resistance.
Inversely
Air flow is ____ proportional to pressure gradient between atmosphere and alveoli
Directly
The lungs expand during inhalation, what happens to the volume and alveolar pressure?
Volume increase
Alveolar pressure decrease
Do lungs expand or recoil during exhalation?
Recoil
What happens to lung volume and alveolar pressure during exhalation?
Volume decrease
Alveolar pressure increase
What pressure causes air to flow into and out of the lungs?
Intrapleural pressure (negative)
Intrapleural pressure is ___ than alveolar and airway pressures
Less
Why must intrapleural pressure be less than alveolar and airway pressure?
To keep the lungs from collapsing
What is transmural pressure?
Pressure between the alveoli and intrapleural space
Due to elastic reoil, lungs want to ____, chest wall wants to ____, and as a result, intrapleural pressure ____ because of ____intrapleural volume.
Collapse ; expand; decreases; increased
How is functional residual capacity determined?
Elastic forces of lung collapse and chest expansion
Emphysema patients show high or low functional residual capacity?
high – more residual air in lungs
Pulmonary fibrosis patients show high or low functional residual capacity?
Low –less residual air in lungs
Emphysema patient has ____ lung compliance and ___ elastance, which means chest wall goes ____.
High; low; outward
Pulmonary fibrosis has ____compliance and ____ elastance, which means chest wall goes ____.
Low; high; inward
What happens when intrapleural pressure is not less than alveolar pressure?
Lung collapses and chest wall springs out! (chest wall wins the tug o war)
Intrapleural pressure is more ____ during inhalation
Negative
During inspiration, when intrapleural pressure gets more negative, what results in lung volume?
Increases
What is the alveolar pressure at the start of inhalation?
Zero, no air flow at that time
What is the alveolar pressure at the end of exhalation?
At zero again.
What is the intrapleural pressure at the end of exhalation?
Very negative
True/False: during inhalation, alveoli expand
True
During exhalation, lungs ____ back to their starting position
Recoil
What is alveolar pressure at the end of exhalation?
0
When is intrapleural pressure most negative?
end of inhalation
How is transmural pressure calculated?
P transmural = P alveolar – P intrapleural
During inspiration, intrapleural pressure becomes more ______, making transmural pressure more ______, allowing the lungs to open and thereby decreasing alveolar pressure.
Negative; positive
During inhalation, which pressures decrease?
Intrapleural and alveolar
True/False: Transmural pressure stays positive through respiration
True, in order to keep airway distended
Why must transmural pressure be positive all the time?
To avoid the lungs from collapsing
During passive exhalation, alveolar pressure _____ atmospheric pressure
Exceeds
Does pressure in the airway increase or decrease during exhalation?
Decrease
True/False: transmural pressure is negative during exhalation
False. Transmural pressure is always positive
During forced expiration, does intrapleural pressure become positive or negative?
Positive
During forced expiration, does alveolar pressure becomes positive or negative?
Positive
What happens to airway pressure during forced expiration?
Airway pressure steadily declines away from the alveoli
In obstructive lung disease, there is a significant loss in which typic of respiratory flow?
Expiratory flow
In restrictive lung disease, which type of respiratory flow is limited?
inhalation; problems with pulling air into lungs due to low lung compliance
What is an example of a restrictive lung disease?
Fibrosis
Fibrosis is what type of lung disease: restrictive or obstructive?
Restrictive
Emphysema is which type of lung disease: restrictive or obstructive?
Obstructive
Asthma is which type of lung disease: restrictive or obstructive?
Obstructive
What is compliance?
Distensibility of the lung
When does lung distend under pressure?
During inhalation
What is elastance?
tendency to recoil back to original volume after distention
When does lung recoil?
During exhalation
Which pulmonary condition is a result of low compliance of lung?
Pulmonary fibrosis
What does it mean when the lungs have low compliance?
It takes a lot more pressure to distend the lungs because the lungs are hard
Which pulmonary condition is a result of high compliance of lung?
Emphysema
What does it mean when the lungs have high compliance?
The lungs are floppy – would distend easily under pressure but unable to recoil back to its original size
What is hysteresis?
Difference in compliance between inflation and deflation
Surface tension makes lung easier or harder to inflate?
Harder
True/False: surface tension creates a collapsing pressure
Smaller alveoli experience greater or lesser collapsing pressure?
Greater
What is laplace’s law and what is it refer to?
Pressure is inversely related to radius
Collapsing pressure of alveoli
How do alveoli overcome these collapsing pressure?
Surfactant
Is alveoli compliance high or low at the start of inflation?
Low because greater collapsing pressure when they are small
Collapsed alveoli is called _____
Atelectasis
Which type of cell secrete surfactant?
Type II alveolar cells
Surfactant ____ surface tension
Reduces
True/False: much like a stretched rubber band, during inhalation, the elastic recoil force of the lungs increases
Ture
True/false: lung expanding force increases during exhalation
True
Elastance and compliance are (inversely/ directly) related
Inversely
High elastance = low compliance
Low elastance = high compliance
What is the x and y axis of a compliance graph?
X axis is airway pressure
Y axis is volume
Parasympathetic nerve effect on bronchiole smooth muscle?
Bronchoconstriction
Sympathetic nerve promotes constriction or dilation of bronchioles?
Dilation
Breathing at higher lung volume, would decrease or increase resistance?
Decrease—because of incomplete exhalations, keeping the airway more distended
What lung volume results in greatest resistance?
Smallest
Resistance and volume are ____ proportional?
Inversely
Greatest resistance is in which sized bronchi?
Medium sized due to turbulent flow
True/False: bronchioles have the highest resistance?
False; bronchioles are actually low resistant
What kind of air flow is in small respiratory airways?
