Respiratory Mechanics IV

Question 1

What are the 2 components that make up the work of breathing

Answer 1

1. Elastic -> stretching the lungs
2. Nonelastic -> moving air through the airways

Question 2

T or F: Chest expansion during inspiration is not resisted by the lungs

Answer 2

F, it is and the amount of resistance determines how much force is needed

Question 3

What are the 3 components of elastic resistance

Answer 3

Question 4

What are 2 characteristics of elastic resistance

Answer 4

Question 5

2 characteristics of the bronchi and bronchioles

Answer 5

Question 6

What are 3 components of nonelastic resistance

Answer 6

Question 7

What are 2 characteristics of nonelastic resistance

Answer 7

Question 8

What is the pleural pressure gradient

Answer 8

Regional variations in intrapleural pressure in resting position (due to gravity) which causes not all parts of the lungs to expand equally

Question 9

Where is pressure greatest in the lung and what happens

Answer 9

Pressure is greatest at top (apex) of the lungs and is at lowest when at base of the lungs. This causes the expanding pressure to be much greater at the top of the lungs resulting in less lung expansion at the apex compared to the base.

Question 10

Explain the slinky affect

Answer 10

Gravity causes the lungs to be more stretched at apex and more compressed at base resulting in greater expansion and ventilation (compliance) at the base

Question 11

Elastic work of breathing depends on

Answer 11

1) Elastic properties of lung tissue (elastin, collagen)
2) Surface tension (tracheobronchial tree line d with fluid film)

Question 12

What is lung compliance

Answer 12

The ease to which something can be stretched

Question 13

What is the difference between lung compliance and elastisity

Answer 13

Elasticity is the ability to oppose stretch and return to its original shape after distortion whereas compliance is the ability to be stretched

Question 14

Hysteresis

Answer 14

Difference between inflation and deflation of lungs usually caused by surface not decreasing surface tension as well in inspiration and due to collapsed alveoli being recruited which is wasteful energy and inspiration has increased resistance due to elastic and air restive properties whereas expiration is just airway resistance

Question 15

Explain this graph

Answer 15

The slope of the curve = compliance
-The slope is higher at lower lung volumes meaning that at lower lung volumes the lungs can more easily expand because they have increased compliance

Question 16

When does lung compliance decrease

Answer 16

1) At high lung volumes (elastin and collagen almost fully stretched (cant move anywhere))
2) At very low lung volumes (increased surface tension because of airway closures (derecruitment))

Question 17

The ease of expansion (Ventilation) depends on

Answer 17

Volume of air already present

Question 18

T or F: All parts of the lung are not equally expanded at rest

Answer 18

T: Regional differences in Ppl

Question 19

What happens at normal resting volumes in terms of ventilation and compliance

Answer 19

Question 20

What happens at residual volume in terms of ventilation and compliance

Answer 20

Question 21

Compare lung compliance between normal, emphysema (obstructive) and lung fibrosis (restrictive)

Answer 21

Question 22

Are inflation and deflation the same

Answer 22

No, the difference between the two is called hysteresis

Question 23

Where along the curve is inflation easier and most difficult

Answer 23

Easier at low lung volumes and more difficult at high lung volumes

Question 24

Is the lung ever completely empty?

Answer 24

No, there is always going to be residual volume

Question 25

What is the pressure required to obtain given lung volumes for inflation and deflation

Answer 25

More pressure is required for given volume during inflation compared to deflation

Question 26

What are 3 characteristics of surface tension

Answer 26

Question 27

What are 2 contributions of surface tension in the lungs

Answer 27

Question 28

Is the lung more compliant when filled with saline or air

Answer 28

More compliant when filled with saline because there is no surface tension with saline as it is a liquid. Surface tension only occurs between gas and liquid therefore lungs have no forces acting on it with a saline solution and are more easily stretched

Question 29

Is the hysteresis the same in a lung filled with saline vs air

Answer 29

Almost no hysteresis when the lung is filled with saline

Question 30

Name 3 characteristics of surfactant

Answer 30

Question 31

Where is surfactant produce

Answer 31

Question 32

What is the function of Type I alveoli

Answer 32

Form the structure of the alveoli

Question 33

What is important about surfactant embryology

Answer 33

Type II alveolar cells take about 36 weeks to reach gestation so the lung collapses if born at 28-32 weeks and infants are at high risk of Respiratory Distress Syndrome if born before 36 weeks

Question 34

Name 3 other characteristics of surfactants

Answer 34

Question 35

What are 5 clinical importance's of surfactant

Answer 35

Question 36

Compare alveolar stability with and without surfactant

Answer 36

Question 37

What is the relationship between surfactant and surface tension

Answer 37

Surfactant impacts surface tension and surface tension impacts lung compliance which determines the amount of elastic work required for breathing

Question 38

The driving pressure required to overcome friction (airway resistance) depends on (2)

Answer 38

1) Rate of airflow (V) -Pattern of airflow

Question 39

What are the 3 types of lung airflow patterns

Answer 39

1. Laminar 2. Transitional 3. Turbulent

Question 40

Describe a laminar airflow pattern

Answer 40

Question 41

Describe a turbulent airflow pattern

Answer 41

Question 42

Describe a transitional airflow pattern

Answer 42

Question 43

Compare the laminar, turbulent and transitional airways in terms of their location, airflow, characteristics, resistance, and driving pressure

Answer 43

Question 44

What does cross-sectional area of airways determine

Answer 44

Overall resistance to flow

Question 45

Explain the changes of airway resistance in terms of lung volumes

Answer 45

The airways caliber (diameter) increases as the lung expands (increased volume) therefore decreasing resistance and increasing conductance of air. Therefore airway resistance decreases on inspiration and increases on expiration

Question 46

Where is the most resistance along different sites (eg. trachea, bronchus, bronchial, terminal bronchiole)

Answer 46

The reason there is more resistance in larger areas is because the air is not streamline vs in the smaller airways its more streamline

Question 47

What are 5 clinical importance about airway resistance

Answer 47

Question 48

What are the 2 roles of lung elastin

Answer 48

Question 49

What are 2 ways to regulate airway caliber

Answer 49

Question 50

What happens in bronchoconstriction in terms of airway caliber and resistance

Answer 50

Question 51

What happens in bronchodilation in terms of airway caliber and resistance

Answer 51

Question 52

How does the ANS regulate constriction and dilation

Answer 52

Question 53

Describe the cough reflex

Answer 53

Question 54

How does noradrenergic cholinergic nervous system impact the bronchial smooth muscle

Answer 54

Question 55

How do inflammatory mediators impact the bronchial smooth muscle

Answer 55

Question 56

Describe how bronchodilation/constriction are caused on a molecular level

Answer 56

Question 57

Differences between a restrictive and obstructive disease

Answer 57

Question 58

Compare inspiration vs expiration

Answer 58