3/4. Ventilation and Compliance 1

Question 1

What is anatomical dead space and what is its volume?

Answer 1

The volume of gas occupied by the conducting airways and this gas is not available for exchange
~150ml

Question 2

What do each of these stand for?

Insert picture

Answer 2

RV = Residual Volume
ERV = Expiratory Reserve Volume 
Vt = Tidal Volume
IRV = Inspiratory Reserve Volume

Question 3

What is the Residual Volume?

Answer 3

1200ml

Question 4

What is the Expiratory Reserve Volume?

Answer 4

1100ml

Question 5

What is the Inspiratory Reserve Volume?

Answer 5

3300ml

Question 6

What is the total lung volume?

Answer 6

5800ml

Question 7

What is the Inspiratory capacity?

Answer 7

3800ml

Question 8

What is the Functional Residual Capacity?

Answer 8

2300ml

Question 9

What is the Vital Capacity?

Answer 9

4600ml

Question 10

Define Tidal Volume

Answer 10

The volume of air breathed in or out of the lungs at each breath

Question 11

Define Expiratory Reserve Volume

Answer 11

The maximum volume of air that can be expelled from the lungs at the end of normal expiration

Question 12

Define Inspiratory Reserve Volume

Answer 12

The maximum volume of air which
can be drawn into the lungs at the end of a normal inspiration

Question 13

Define Residual Volume

Answer 13

The volume of gas in the lungs at the end of a maximal expiration

Question 14

Define Vital Capacity

Answer 14

Vital Capacity = tidal volume + inspiratory reserve volume +
expiratory reserve volume

Question 15

Define Total Lung Capacity

Answer 15

Total Lung Capacity = vital capacity + the residual volume

Question 16

Define Inspiratory Capacity

Answer 16

Inspiratory Capacity = tidal volume + inspiratory reserve volume

Question 17

Define Function Residual Capacity

Answer 17

Functional Residual Capacity = expiratory reserve volume +
residual volume

Question 18

Define FEV1

Answer 18

Forced Expired Volume in 1 second

Question 19

Define FEV1:FVC

Answer 19

Fraction of Forced Vital Capacity expired in 1 second

Question 20

What does the term “Ventilation” refer to?

Answer 20

Movement of air in and out of the lungs (breathing)

Question 21

What are the 2 more specific kinds of ventilation?

Answer 21

Pulmonary (Minute) Ventilation

Alveolar Ventilation

Question 22

Define Pulmonary (Minute) Ventilation

Answer 22

Total air movement into/out of the lungs (relatively insignificant in functional terms)

Question 23

Define Alveolar Ventilation

Answer 23

FRESH air getting to the alveoli and therefore available for gas exchange (functionally much more significant)

Question 24

If a person is breathing rapidly but with shallow breaths are they hyperventilating or hypo-ventilating?

Answer 24

Hypo-ventilating as not enough air is being passed into the lungs

Question 25

Define partial pressure

Answer 25

Pressure of a gas in a mixture of gases is equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whole gaseous mixture

Question 26

If all gas molecules exert the same pressure, what does this mean for partial pressure?

Answer 26

Partial pressure increases with increasing [gas] mixture

Question 27

During Hyper-ventilation which is higher PO2 or PCO2?

Answer 27

PO2 is higher than PCO2

Question 28

What is the relationship between PO2 and PCO2 in normal conditions?

Answer 28

They both remain fairly constant

Question 29

What is normal alveolar ventilation?

Answer 29

4.2 L/min

Question 30

What are properties of healthy lungs?

Answer 30

• Very Elastic
• Stretched slightly open even at the end of relaxed expiration
• Natural tendency to recoil

Question 31

What 2 cells are the alveolar wall made up of and what are their functions?

Answer 31

Type 1 Cells - Thin walled and permit gas exchange

Type 2 Cells - specialised and secrete surfactant fluid

Question 32

What is Surfactant and where is it produced?

Answer 32

Detergent like fluid produced in the Type 2 alveolar cells

Question 33

What functions does surfactant provide?

Answer 33

• Reduces surface tension and reduces tendency for alveoli collapse
• Increases lung compliance (distensibility)
• Reduces lung’s tendency to recoil
• Makes work of breathing easier
• Is more effective in small alveoli than large alveoli

Question 34

Where does surface tension occur?

Answer 34

Wherever there is an air-water interface and refers to the attraction between water molecules