Lecture 5 (Test 2)

Question 1

What does spirometry measure?

Answer 1

Spirometry measures how lung volume changes as someone breathes, including normal breathing and deep breathing.

Spirometry tracks the air coming into and leaving the patient.

Question 2

What are the three main lung volumes measured by spirometry?

Answer 2

• Tidal Volume (TV)
• Inspiratory Reserve Volume (IRV)
• Expiratory Reserve Volume (ERV)

Question 3

What is vital capacity?

Answer 3

Vital capacity is the total volume of air that can be inhaled and exhaled in a single maximal effort breath, calculated as TV + IRV + ERV.

It represents the working volume of the lungs.

Question 4

What is a limitation of basic spirometry?

Answer 4

Basic spirometry cannot measure any lung capacities that include residual volume (RV) and functional residual capacity (FRC).

Residual volume cannot be expelled from the lungs for measurement.

Question 5

What is the purpose of using an indicator gas in advanced spirometry?

Answer 5

An indicator gas, like helium, is used to measure lung volumes that cannot be expelled, such as residual volume and functional residual capacity.

Helium is cheap and inert, making it suitable for these measurements.

Question 6

How does the dilution of helium help in measuring lung volume?

Answer 6

The dilution of helium in the lungs indicates how much air is present; knowing the starting concentration and volume allows calculation of lung volumes.

The final concentration helps determine the volume of air in the lungs.

Question 7

What is pulmonary compliance?

Answer 7

Pulmonary compliance refers to the ease with which the lungs expand under pressure.

It is represented by the slope of the pressure-volume curve.

Question 8

How does emphysema affect lung compliance?

Answer 8

Emphysema increases lung compliance due to the loss of elastic tissue, making it easier to fill the lungs but harder to expel air.

Question 9

What characterizes restrictive lung diseases?

Answer 9

Restrictive lung diseases are characterized by low compliance, making it harder to fill the lungs with air.

Examples include pulmonary fibrosis.

Question 10

What is hysteresis in lung function?

Answer 10

Hysteresis refers to the difference in lung behavior during inspiration and expiration.

Question 11

How does the lung behave differently during inspiration and expiration?

Answer 11

The lung is generally more compliant during expiration than during inspiration, leading to a delay in air intake at low lung volumes.

Question 12

What happens when air in the lungs is replaced with saline?

Answer 12

Replacing air with saline reduces hysteresis and increases compliance, making the lung behavior similar during inspiration and expiration.

Question 13

What causes the difference in compliance between air-filled and saline-filled lungs?

Answer 13

The difference is caused by surface tension in the alveoli, which is affected by the presence of air.

Question 14

What is the primary indicator gas used in advanced spirometry?

Answer 14

Helium is the primary indicator gas used due to its cost-effectiveness and inert properties.

Question 15

What is the formula to calculate vital capacity from total lung capacity and residual volume?

Answer 15

TLC - RV = VC

Question 16

True or False: Obstructive lung diseases typically result in reduced lung volumes.

Answer 16

False.

Obstructive lung diseases often result in abnormally high lung volumes.

Question 17

What is pulmonary compliance?

Answer 17

The ability of the lungs to expand and contract in response to pressure changes.

Question 18

What contributes to the compliance of the pulmonary system?

Answer 18

Surface tension is a large contributor to the overall compliance of the system.

Question 19

What is the air-water interface in the alveoli?

Answer 19

It is the area where water meets gas or air inside the alveoli.

Question 20

What effect does high surface tension have on inhalation?

Answer 20

It makes it difficult to put air into the lungs.

Question 21

What role does surfactant play in the lungs?

Answer 21

Surfactant reduces surface tension, making it easier to fill the lungs with air.

Question 22

What are the two main components of surfactant?

Answer 22

• Lipids (90%)
• Proteins (10%)

Question 23

What are the four surfactant proteins?

Answer 23

• SP-A
• SP-B
• SP-C
• SP-D

Question 24

Which surfactant proteins are hydrophilic?

Answer 24

• SP-A
• SP-D

Question 25

Which surfactant proteins are hydrophobic?

Answer 25

* SP-B * SP-C

Question 26

What are the two most important phosphatidyl compounds in surfactant?

Answer 26

* Dipalmitoylphosphatidylcholine (31%) * Unsaturated Phosphatidylcholine (31%)

Question 27

What type of cells produce surfactant in the lungs?

Answer 27

* Goblet cells (upper airway) * Clara cells (lower airways) * Type 2 alveolar cells (alveoli)

Question 28

What is the primary function of type 1 cells in the alveoli?

Answer 28

Gas exchange.

Question 29

What is the primary function of type 2 cells in the alveoli?

Answer 29

Production of surfactant.

Question 30

What is the process by which surfactant is released?

Answer 30

Exocytosis.

Question 31

What percentage of the gas exchange surface area is made up by type 1 cells?

Answer 31

90 to 95%

Question 32

What percentage of the gas exchange surface area is made up by type 2 cells?

Answer 32

5 to 10%

Question 33

What is tubular myelin?

Answer 33

A netting structure where surfactant proteins and lipids are stored.

Question 34

How does surfactant function during normal breathing?

Answer 34

Surfactant molecules are knocked off the netting and reduce surface tension at the air-water interface.

Question 35

What happens to surfactant over time?

Answer 35

It falls apart and needs to be recycled by alveolar macrophages.

Question 36

What is the role of alveolar macrophages?

Answer 36

To digest and recycle surfactant and remove debris.

Question 37

What happens if surfactant production is not balanced with its decay?

Answer 37

Increased surface tension and difficulty in lung inflation.

Question 38

How does negative alveolar pressure affect surfactant?

Answer 38

It helps to pull surfactant off the netting during inspiration.

Question 39

How does positive pressure ventilation differ in effect on surfactant compared to negative pressure?

Answer 39

It does not knock off surfactant in the same way as negative pressure does.

Question 40

What effect does negative alveolar pressure have on surfactant?

Answer 40

Negative alveolar pressure likely pulls surfactant off the netting.

Question 41

How does positive pressure ventilation affect surfactant compared to negative pressure?

Answer 41

Positive pressure ventilation does not have the same effect on surfactant as negative pressure inspiration.

Question 42

What happens to surfactant in a collapsed section of the lung?

Answer 42

Surfactant in the collapsed area will run out due to lack of air filling and recoiling.

Question 43

What is the challenge in recruiting a collapsed area of the lung?

Answer 43

The challenge is that surface tension is higher in the collapsed area compared to open areas.

Question 44

What role do Goblet cells play in the lungs?

Answer 44

Goblet cells are primarily mucus-secreting cells.

Question 45

What are Clara cells?

Answer 45

Clara cells are another type of cell found in the lungs.

Question 46

What are the two types of alveolar cells?

Answer 46

Type one and type two alveolar cells.

Question 47

What is the function of mast cells in the lungs?

Answer 47

Mast cells release inflammatory mediators, such as histamine.

Question 48

How many alveoli are typically found in young adults?

Answer 48

Approximately 500 million alveoli.

Question 49

What is alveologenesis?

Answer 49

The process of forming new alveoli in the lungs.

Question 50

How many capillaries are estimated to be attached to each alveolus?

Answer 50

Up to 1,000 capillaries.

Question 51

What is the average alveolar surface area in a healthy 20-year-old adult?

Answer 51

About 70 square meters.

Question 52

What is surface tension in the context of the lungs?

Answer 52

Surface tension is the force that causes water molecules to aggregate and affects air entry into alveoli.

Question 53

What percentage of elastic recoil pressure is due to surface tension?

Answer 53

About 2/3 of normal elastic recoil pressure.

Question 54

How does restrictive lung disease affect lung volumes?

Answer 54

Restrictive lung disease results in lower lung volumes due to increased tissue recoil.

Question 55

How does obstructive lung disease affect lung volumes?

Answer 55

Obstructive lung disease results in higher lung volumes due to decreased tissue recoil.

Question 56

What happens to surface tension in lung diseases?

Answer 56

There is usually a surfactant deficiency associated with every lung disease.

Question 57

Fill in the blank: The force that allows water molecules to aggregate is called _______.

Answer 57

surface tension

Question 58

True or False: Surface tension is usually a significant factor in lung function.

Answer 58

False

Question 59

What happens to water molecules in a container over time?

Answer 59

They aggregate to form droplets due to surface tension.

Question 60

What is the relationship between elastic recoil and tissue factors?

Answer 60

Elastic recoil pressure is influenced by tissue elasticity and surface tension.

Question 61

What do water molecules prefer to interact with?

Answer 61

Other water molecules ## Footnote Water molecules do not prefer to interact with air and tend to aggregate with each other.

Question 62

What happens when water droplets are placed on glass and moved?

Answer 62

They form and aggregate on the side of the glass ## Footnote This aggregation occurs because water molecules prefer to be close to each other.

Question 63

What is an amphipathic molecule?

Answer 63

A molecule that is partially water soluble and partially lipid soluble ## Footnote These molecules tend to position themselves at the air-water interface.

Question 64

Where does a phospholipid orient itself in a water solution?

Answer 64

At the air-water interface with the polar head in water and the lipid tail sticking out ## Footnote This orientation minimizes the interaction of the lipid tail with water.

Question 65

What role do surfactants play in water molecules?

Answer 65

They prevent water molecules from clumping together ## Footnote Surfactants can insert themselves between water molecules, reducing surface tension.

Question 66

What is surface tension?

Answer 66

The force generated by water molecules wanting to be around other water ## Footnote Surface tension causes water molecules to be attracted to each other, which can lead to droplet formation.

Question 67

How do surfactants affect the alveoli?

Answer 67

They reduce surface tension, making alveoli more compliant ## Footnote This allows for easier filling of the lungs with air.

Question 68

What is the source of surfactants in the alveolus?

Answer 68

Type II cells and their associated mesh ## Footnote These cells help produce surfactants that are essential for lung function.

Question 69

What happens to surfactants under negative alveolar pressure?

Answer 69

They get nudged off the mesh and swim to the air-water interface ## Footnote This positioning is crucial for effective lung function.

Question 70

What effect does surfactant have on lung hydration?

Answer 70

It helps keep the lungs dry ## Footnote Surfactants create a thinner layer of water, facilitating gas exchange.

Question 71

How does lung volume affect airway resistance?

Answer 71

Higher lung volumes lead to lower airway resistance ## Footnote Conversely, lower lung volumes increase airway resistance.

Question 72

What happens to airway diameter at lower lung volumes?

Answer 72

The airway diameter decreases ## Footnote This increased resistance limits the speed of exhalation.

Question 73

What is the relationship between lung volume and exhalation speed?

Answer 73

High lung volumes = low airway resistance = faster exhalation ## Footnote Low lung volumes increase airway resistance, slowing exhalation.

Question 74

What holds larger airways open during normal breathing?

Answer 74

Negative pleural pressure ## Footnote This traction helps maintain airway patency.

Question 75

What is the role of connective tissue in lung function?

Answer 75

It tethers lung components together, aiding in air intake ## Footnote Without these connections, air intake can be compromised.

Question 76

How does negative pleural pressure affect alveoli and airways?

Answer 76

It helps maintain airway patency and allows for high alveolar volume ## Footnote This is essential for effective gas exchange in the lungs.