Lung Volumes And Capacities Flashcards
Is the volume inspired or expired with each normal breath.
Tidal volume (VT)
Is the volume that can be inspired over and above the tidal volume.
Inspiratory reserve volume (IRV)
It is used during exercise.
Inspiratory reserve volume (IRV)
Is the volume that can be expired after the expiration of a tidal volume.
Expiratory reserve volume (ERV)
Is the volume that remains in the lungs after a maximal expiration.
Residual volume (RV)
It cannot be measured by spirometry.
Residual volume
Is the volume of the conducting airways.
Anatomic dead space
Is normally approximately 150 mL.
Anatomic dead space
Is a functional measurement.
Physiologic dead space
Is defined as the volume of the lungs that does not participate in gas exchange.
Physiologic dead space
Is approximately equal to the anatomic dead space in normal lungs.
Physiologic dead space
It may be greater than the anatomic dead space in lung diseases in which there are ventilation/perfusion (V/Q) defects.
Physiologic dead space
VD
Physiologic dead space
Physiologic dead space formula:
VD = VT x PaCO2 - PeCO2/PaCO2
Minute ventilation is expressed as follows:
Minute ventilation = VT x Breaths/min
Alveolar ventilation is expressed as follows:
VA = (VT - VD) x Breaths/minute
Is the sum of tidal volume and RV.
Inspiratory capacity
Is the sum of ERV and RV.
Functional residual capacity (FRC)
Is the volume remaining in the lungs after a tidal volume is expired.
Functional residual capacity (FRC)
True or False:
Functional residual capacity (FRC) can be measured by spirometry.
False: It cannot be measured by spirometry. It includes the RV.
Is the sum of tidal volume, IRV and ERV.
Vital capacity (VC) or Forced Vital Capacity (FVC)
Is the volume of air that can be forcibly expired after a maximal inspiration.
Vital capacity (VC) or Forced Vital Capacity (FVC)
Is the sum of all four lung volumes.
Total lung capacity (TLC)
Is the volume in the lungs after a maximal inspiration.
Total lung capacity (TLC)
True or False
Total lung capacity cannot be measured by spirometry.
True
Is the volume of air that can be expired in the first second of a forced maximal expiration.
Forced expiratory volume (FEV1)
Forced expiratory volume (FEV1) is normally ____% of the forced vital capacity which is expressed as:
80%
FEV1 / FVC = 0.8
In obstructive lung disease, such as asthma and chronic obstructive pulmonary disease (COPD), both FEV and FVC are ______________, but FEV1 is reduced more than FVC is: thus, FEV1/FVC is _______________.
Reduced
Decreased
In restrictive lung disease, such as fibrosis, both FEV1 and FVC are ___________ but FEV1 is reduced less than FVC is: thus, FEV1/FVC is _______________.
Reduced
Increased
Is the most important muscle for inspiration.
Diaphragm
When the diaphragm contracts, the abdominal contents are pushed ________ ,and the ribs are lifted ___________ and __________, __________ the volume of the thoracic cavity.
Downward
Upward and outward
Increasing
Are not used for inspiration during normal quiet breathing.
External intercostals and accessory muscles
Are used during exercise and respiratory distress.
External intercostals and accessory muscles
Expiration is normally _________.
Passive
True or False:
Because the lung-chest wall system is elastic, it returns to its resting position after inspiration.
True
Are used during exercise or when airway resistance is increased because of disease (asthma).
Expiratory muscles
Compress the abdominal cavity, push the diaphragm up, and push air out of the lungs.
Abdominal muscles
Pulls the ribs downward and inward.
Internal intercostals muscles
Is analogous to capacitance in the cardiovascular system.
Compliance of the respiratory system
Compliance of the respiratory system is described by the following:
C = V / P
Describes the distensibility of the lungs and chest wall.
Compliance of the respiratory system
Is inversely related to elastamce, which depends on the amount of elastic tissue.
Compliance of the respiratory system
Is inversely related to stiffness.
Compliance of the respiratory system
Is the slope of the pressure-volume curve.
Compliance of the respiratory system
Is the change in volume for a given change in pressure. Pressure can refer to the pressure inside the lungs and airways or to transpulmonary pressure.
Compliance of the respiratory system
Is alveolar pressure minus intrapleural pressure.
Transmural pressure
When the pressure outside the lungs is ___________, the lungs expand and lung volume increases.
Negative
When the pressure outside of the lungs is ______________, the lungs collapse and lung volume decreases.
Positive
Inflation of the lungs (inspiration) follows a different curve than deflation of the lungs (expiration); this difference is called ____________ and is due to the need to overcome surface tension forces when inflating the lungs.
Hysteresis
In the middle range of pressures, compliance is _________ and the lungs are _______________ and the curve flattens.
Lowest
Least distensible
Is less than that of the lungs alone or the chest wall alone (the slope is flatter).
Compliance of the lung-chest wall system
At __________, lung volume is at FRC and the pressure in the airways and lungs is equal to atmospheric pressure.
Rest
Under these equilibrium conditions, there is a collapsing force on the lungs and an expanding force on the chest wall. At _____, these two forces are EQUAL AND OPPOSITE and, therefore, the combined lung-chest wall system NEITHER wants to collapse nor wants to expand.
FRC
As a result of these two opposing forces, intrapleural pressure is ____________ (subatmospheric).
Negative
If air is introduced into the intrapleural space (pneumothorax), the intrapleural pressure becomes ___________ to the atmospheric pressure.
Equal
True or False:
Without the normal negative intrapleural pressure, the lungs will collapse (their natural tendency) and the chest wall will spring outward (its natural tendency).
True
In a patient with __________, lung compliance is increased and the tendency of the lungs to collapse is decreased.
Emphysema
The lung-chest wall system will seek a new, higher FRC so that the two opposing forces can be balanced again.
Emphysema
The patient’s chest becomes barrel-shaped, reflecting this higher volume.
Emphysema
In a patient with ____________, lung compliance is decreased and the tendency of the lungs to collapse is increased.
Fibrosis
The lung-chest wall system will seek a new,lower FRC so that the two opposing forces can be balanced again.
Fibrosis
Results from the attractive forces between liquid molecules lining the alveoli at the air-liquid interface.
Surface tension of the alveolie
Creates a collapsing pressure that is directly proportional to surface tension and inversely proportional to alveolar radius.
Laplace’s law
Have low collapsing pressure and are easy to keep open
Large alveoli
Have high collapsing pressures and are more difficult to keep open.
Small alveoli
In the absence of surfactant, the small alveoli have a tendency to collapse or _________________.
Atelectasis
Lines the alveoli.
Surfactant
Reduces surface tension by disrupting the intermolecular forces between liquid molecules.
Surfactant
This reduction in surface tension prevents small alveoli from collapsing and ____________ compliance.
Increases
Surfactant is synthesized by ________________ and consists primarily of the phospholipid __________________.
Type II alveolar cells
Dipalmitoylphosphatidylcholine (DPPC)
In the FETUS, surfactant synthesis is variable. Surfactant may be present as early as gestational week ___ and is almost always present by gestational week ____.
24
35
Generally, a lecithin:sphingomyelin ratio greater than ________ in amniotic fluid reflects mature levels of surfactant.
2:1
______________________ can occur in premature infants because of the lack of surfactant. The infant exhibits ATELECTASIS (lungs collapse), difficulty reinflating the lungs (as a result of decreased compliance) and HYPOXEMIA (as a result of decreased V/Q).
Neonatal respiratory distress syndrome
Is driven by, and is directly proportional to the PRESSURE DIFFERENCE between the mouth or nose and the alveoli.
Airflow
Is inversely proportional to airway resistance; thus the higher the airway resistance, the lower the airflow.
Airflow
Is described by Poiseuille’s law.
Resistance of the airways
The major site of airway resistance is the ___________________.
Medium-sized bronchi
True or False:
The smallest airways would seem to offer the highest resistance, but they do not because of their parallel arrangement.
True
Changes airway resistance by altering the radius of the airways.
Contraction or relaxation of bronchial smooth muscle
PARASYMPATHETIC STIMULATION, irritants and the slow-reacting substance of anaphylaxis (asthma) ___________ the airways, __________ the radius and ____________ the resistance to airflow.
Constrict
Decrease
Increase
SYMPATHETIC STIMULATION and sympathetic agonists (ISOPROTERENOL) ____________ the airways, via ______________, _________ the radius, and ___________ the resistance to airflow
Dilate
B2 receptors
Increase
Decrease
Alters airway resistance because of the radial traction exerted on the airways by surrounding lung tissue.
Lung volume
__________________ are associated with greater traction on airways and decreased airway resistance.
High lung volumes
_______________ are associated with less traction and increased airways resistancce, even to the point of airway collapse.
Low lung volumes
True or False:
Viscosity or density of inspired gas does not change the resistance to airflow.
False:
Changes the resistance to airflow.
During a deep-sea dive, both air density and resistance to airflow are ______________.
Increased
Breathing a low-density gas, such as helium ____________ the resistance to airflow.
Reduces
Because lung pressures are expressed relative to atmospheric pressure, alveolar pressure is said to be _______.
Zero
True or False:
At FRC, the opposing forces of the lungs trying to collapse and the chest wall trying to expand create a negative pressure in the intrapleural space between them
True
Intrapleural pressure can be measured by a _______________________.
Balloon catheter in the esophagus.
Lung volume is the _____.
FRC
The inspiratory muscles contract and cause the volume of the thorax to _________.
Increase
As lung volume increases, alveolar pressure ___________ to less than atmospheric pressure.
Decreases
The ____________ between the atmosphere and the alveoli now causes air to flow into the lungs; airflow will continue until the pressure gradient dissipates.
Pressure gradient
True or False:
Because lung volumes increases during insipiration, the elastic recoil strength of the lungs also decreases.
False
Increases
Changes in intrapleural pressure during inspiration, are used to measure the _________________ of the lungs.
Dynamic compliance
At the peak of inspiration, lung volume is the FRC plus __________.
One VT
During expiration alveolar pressure becomes ________ than atmospheric pressure.
Greater
____________ returns to its resting value during a normal (passive) expiration.
Intrapleural pressure
However, during a forced expiration, intrapleural pressure actually becomes ___________.
Positive
In ________, in which airway resistance is increased patients learn to expire slowly with “pursed lips” to prevent the airway collapse that may occur with a forced expiration.
COPD
COPD is a combination of ______ and _______.
Chronic bronchitis and emphysema
COPD is an obstructive disease with _______ lung compliance in which expiration is impaired,
Increased
_______________ (primarily emphysema) have mild hypoxemia with cyanosis and alveolar ventilation, normocapnia (normal PCO2).
Pink puffers
________________ (primarily bronchitis) have severe hypoxemia with cyanosis and becaus they do not maintain alveolar ventilation, hypercapnia (increased PCO2). They have right ventricular failure and systemic edema.
Blue bloaters
_________ is a restrictive disease with decreased lung compliance in which inspiration is impaired.
Fibrosis
Is characterized by a decrease in all lung volumes.
Fibrosis
