Exam 2: 4 Mar Understanding FRC, Lung Mechanics, & Advanced Spirometry Flashcards
What does FRC stand for?
Functional Residual Capacity
What is the role of helium in advanced spirometry?
It is used as an indicator gas to measure residual volume (RV) and total lung capacity.
What is vital capacity?
The total volume of air that can be exhaled after a maximal inhalation.
What is the relationship between lung volume and airway resistance?
Higher lung volumes result in lower airway resistance.
How does surfactant affect surface tension in the lungs?
Surfactant reduces surface tension, which is crucial for lung compliance and gas exchange.
What is the significance of error bars in measuring FRC?
Error bars indicate variability in measurements and can suggest trends even if specific data points are not statistically significant.
What is the impact of surfactant deficiency on lung diseases?
It leads to increased surface tension and difficulty in inflating the lungs.
Fill in the blank: The basic spirometry is incapable of measuring anything that has ______ as a component.
residual volume (RV)
What are the types of alveolar cells involved in surfactant production?
- Goblet cells
- Club (Clara) cells
- Type II alveolar cells
What is the mechanism of surfactant release from alveolar cells?
Exocytosis
True or False: Surfactant is produced only by type II alveolar cells.
False
Surfactant is also produced by goblet cells in the upper airway, as well as the Clara/club cells in the alveoli.
What happens to helium concentration in the lungs during lung volume measurement?
It decreases as it gets diluted/equilibrated with the volume of air in the lungs.
What is the importance of maintaining surfactant levels in the lungs?
It is crucial for proper lung function and preventing complications.
What is the relationship between lung tissue and compliance?
Normal and elastic tissues enhance compliance, while conditions like emphysema and fibrosis affect it negatively.
What is transpulmonary pressure? Why is it important?
The difference between alveolar pressure and pleural pressure. PTP is responsible for alveolar inflation
What is the effect of pleural pressure on airway resistance?
It helps to hold airways open, affecting airway resistance.
- In normal, negative pressure, breathing, the more negative the pleural pressure, the more positive the transpulmonary pressure which will stretch the alveoli and bring air into them.
What advanced spirometry technique is used to estimate FRC?
Using an indicator gas like helium to measure dilution.
Other noble gases that can be used are: Neon (Ne), Argon(Ar), Xenon (Xe), Radon (Rn) and Ununoctium (Uuo). These are all inert.
What are the consequences of increased airway resistance?
It can lead to difficulty in breathing and reduced airflow.
Fill in the blank: The total lung capacity is the sum of vital capacity and ______.
residual volume (RV)
What is the role of macrophages in lung health?
They recycle surfactant components and maintain lung health.
What are the common lung diseases associated with surfactant deficiency?
- COPD (Obstructive)
- Asthma (Obstructive)
- Fibrosis (Restrictive)
All pulmonary diseases have a surfactant deficiency.
What is the function of surfactant proteins and phospholipids?
They help maintain lung health by reducing surface tension (Water pooling).
- Because they are amphipathic, the hydrophilic head seats between water molecules while the hydrohobic tail points out toward the alveolar lumen.
- This reduction in surface tension creates a more dry lung and keeps the water layer thin for effective gas exchange.
What are the noble gases that can be used in PFTs?
Helium, Neon, Argon, Xenon, Radon(Inert form)
Not Krypton or Ununoctium
What should you check for if you have a basement in areas where radon is common?
Radon gas
- This is not inert like its pure form on the periodic table.
Radon is the 2nd leading cause of lung cancer, behind smoking.
What is emphysema characterized by?
Loss of elastic tissue in the lungs
- The springs lose their recoil
What does decreased elastic recoil in emphysema lead to?
Difficulty in expelling air from the lungs
- TLC, FRC, and RV increase
- ERV, and VC decrease
What is the effect of restrictive lung diseases on lung compliance?
They result in low compliance, making it harder to fill the lungs
- More tissue adds to the existing PTP resulting in
- TLC, VC, FRC, and RV decrease
What is one example of a restrictive lung disease?
Fibrosis
What happens to lung volumes in obstructive lung diseases?
They are usually at abnormally high lung volumes
What is hysteresis in lung function?
The difference in behavior of the lungs during inspiration and expiration
How does the lung behave during a large inspiration?
It may initially resist expansion due to low compliance at low lung volumes
What is the result of filling the lungs with saline instead of air?
Narrowed difference in compliance between inspiration and expiration
What contributes significantly to the compliance of the lungs?
Surface tension created by the air-water interface in the alveoli
What is surfactant?
What are its main components?
A substance that reduces surface tension in the lungs
Lipids and surfactant proteins
What are the surfactant lipids and proteins called? What are their distributions
Lipids: Phosphatidylcholine (31%) and Dipalmitoylphosphatidylcholine (31%)
- These two are amphipathic
Proteins: SP-A, SP-B, SP-C, SP-D
- SPAD=Splash: SP-A and SP-D are hydrophilic
- SP-B and SP-C are hydrophobic
What is a key phospholipid in surfactant composition? This may be a good spelling term…
Dipalmitoylphosphatidylcholine
Fill in the blank: The second leading cause of lung cancer is _______.
Radon gas
True or False: Emphysema is characterized by an increase in elastic tissue.
False
What happens to lung compliance in the presence of surfactant?
It increases, making it easier to inhale air
What are phosphatidyl compounds?
Precursors to surfactant, especially phosphatidylcholine and dipalmitoylphosphatidylcholine since these two alone make up 62% of the lipid surfactant
Other lipid surfactants that Dr. Schmidt might want us to know are phosphatidyls-ethanolamine, inositol, glycerol, serine and sphingomyelin
What is the structure of phosphatidyl compounds?
Amphipathic molecules with a long fatty acid tail and a charged head
This allows them to interact with both water and oil.
What are goblet cells?
Secretory cells in the upper airway that produce mucus and a small amount of surfactant
They are important for maintaining moisture in the airway.
What are Clara cells also known as?
Club cells
These are secretory cells in the lower airways that produce surfactant.
What type of cells primarily produce surfactant in the alveoli?
Type II alveolar cells
- These cells are interspersed among type I cells in the alveoli.
- They only take up about 5% of the alveolar surface area but are 2X greater in number than type 1 cells.
What is the function of type I alveolar cells?
Major gas exchange cells in the lung
They are thin and flat to facilitate gas diffusion.
What is the process by which surfactant is released?
Exocytosis
This process allows surfactant to be stored and then released into the alveoli.
What percentage of the surface area of the alveoli is made up of type I cells?
How much alveolar surface are do the lungs typically have?
90 to 95%
- 70m2 (about the size of a tennis court!!)
This large surface area is crucial for effective gas exchange.
What is the role of alveolar macrophages?
To digest and recycle surfactant and other debris in the lungs
They help maintain lung health by clearing out waste.
What happens to surfactant when it is not replenished?
Surface tension increases in the lung, making it harder to inflate
This can lead to respiratory complications.
What is tubular myelin?
A storage structure for surfactant in the alveoli
- Surfactant proteins and lipids are stored in this mesh-like structure. During normal, negative pressure, ventilation, the transpulmonary pressure stretching the alveoli bumps off surfactanct, allowing surfactanct to contribute to reducing surface tension.
What is the effect of positive pressure ventilation on surfactant release?
It may not effectively release surfactant compared to negative pressure breathing. Some surfactant does get knocked off the tubular myelin but gas exchange is still impaired due to the increased width of the water layer.
What happens to surfactant in collapsed areas of the lung?
It runs out and surface tension increases
- Later recruitment of collapsed lungs is more difficult so reinflation can be challenging.
- This recruitment can require much higher transpulmonary pressures which can cause damage to tissues (especially if pt requires PEEP)
True or False: Type II cells are more numerous than type I cells in the alveoli.
True
However, type I cells cover a much larger surface area.
What happens to surfactant molecules as they are used?
They fall apart over time and need to be replaced.
- Replacement occurs via reuptake of degraded molecules into the Type-II cells.
This cycle is essential for maintaining effective lung function.
What are goblet cells primarily responsible for?
Goblet cells are primarily mucus-secreting cells.
Did you say surfactant? Ya me either silly. (But they do that too)
Goblet cells play a crucial role in maintaining moisture and trapping particles in the respiratory tract.
What are Clara cells and where are they found?
Clara cells are a type of alveolar cell found in the lungs.
- Clara cells help in detoxifying harmful substances inhaled into the lungs.
- They also produce a small amount of surfactant.
What is the estimated number of alveoli in a young adult’s lungs?
Approximately 500 million alveoli.
This number decreases with age and certain lung diseases.
What happens to alveoli when a lung is removed?
The remaining lung may produce new alveoli, but at a very slow rate.
This regeneration capacity is limited and varies with age and health.
What is the surface area available for gas exchange in a healthy 20-year-old adult’s lungs?
About 70 square meters, roughly the size of a tennis court.
This large surface area is critical for efficient gas exchange.
What is elastic recoil pressure in the lungs?
Elastic recoil pressure is the tendency of alveoli to recoil due to tissue elasticity and surface tension.
This pressure is essential for expelling air from the lungs.
What components contribute to elastic recoil pressure?
Elastic recoil pressure is approximately 1/3 due to tissue factors and 2/3 due to surface tension.
This balance is vital for lung function.
True or False: Surface tension in the lungs is not regulated under normal conditions.
False.
- Surface tension is highly regulated to facilitate lung function.
- This will ALWAYS be the case unless the lungs are damaged.
What is the effect of high surface tension on lung function?
High surface tension can make it harder to open parts of the lung.
This is particularly problematic in lung diseases.
What is surfactant and where is it produced?
Surfactant is a substance that reduces surface tension in the lungs and is produced by type II alveolar cells, .
Surfactant is crucial for preventing alveolar collapse.
What is the relationship between surfactant deficiency and lung diseases?
Surfactant deficiency is observed in every lung disease studied, such as COPD and asthma.
This deficiency contributes to impaired lung function.
Fill in the blank: The property of water that causes it to want to group together is called _______.
[surface tension]
What is the role of surfactants at the air-water interface in the alveoli?
Surfactants prevent water molecules from clumping together, reducing surface tension.
This action helps maintain alveolar stability and compliance.
What happens to the water molecules in a droplet when surfactant is added?
Surfactant prevents water molecules from sticking together, allowing them to spread out.
This principle is used in dishwashing to prevent water spots.
What happens to lung volumes in restrictive lung diseases?
Lung volumes are lower due to increased tissue recoil from scar tissue.
This makes it harder to fill the lungs with air.
What is the impact of obstructive lung diseases on lung volumes?
Lung volumes are higher due to reduced elastic tissue resistance.
This allows for easier filling of the lungs.
How does transpulmonary pressure affect lung volumes in different lung conditions?
Normal lungs have intermediate lung volumes, restrictive diseases have lower, and obstructive diseases have higher volumes.
This relationship is crucial for understanding lung mechanics.
What happens to surfactants when negative pressure is applied?
Surfactants get nudged off the mesh and swim to the air-water interface.
What is the orientation of phospholipids at the air-water interface?
The head of the phospholipid is in the water, and the fatty tails are oriented into the air.
What is the role of surfactants in the lungs?
Surfactants reduce surface tension and help keep the lungs dry.
How does surfactant affect gas exchange?
Surfactant allows for a thinner layer of water, facilitating gas exchange.
What is the relationship between lung volume and airway resistance?
Higher lung volumes correlate with lower airway resistance.
What happens to airway resistance when lung volume decreases?
Airway resistance increases.
What is the effect of high lung volume on alveoli and airway diameter?
At high lung volumes, alveoli are larger and airway diameter is wider.
True or False: Lower lung volumes make it easier to exhale.
False.
What physical factor helps keep larger airways open?
Negative pleural pressure.
What happens to airways at high lung volumes?
They are held open by negative pleural pressure.
Fill in the blank: The _______ pressure helps build the lung up with air.
transpulmonary
What is the effect of connective tissue on lung function?
It helps hold the lung structures together and supports airway opening.
How does airway resistance change with forced expiration from low lung volume?
It limits the speed of exhalation.
What is the impact of lung volume on pulmonary blood flow?
Higher lung volumes can influence blood flow and pulmonary blood pressures.
What occurs to the airway diameter when the alveolus is at residual volume (RV)?
The airway diameter becomes narrower.
What must be applied to reach total lung capacity?
A transpulmonary pressure of positive 30.
How does negative pleural pressure affect smaller airways?
It helps keep them open through volume expansion.
What is the significance of the air-water interface in lung function?
It is crucial for effective gas exchange.
Fill in the blank: Surfactants help _______ the surface tension in the lungs.
reduce
What happens to airway resistance at lower lung volumes?
It increases due to narrower airways.
True or False: Surfactants have no effect on keeping the lungs dry.
False.
What is the relationship between airway resistance and the diameter of airways?
Narrower airways increase resistance.
