Session 2 - Lung Ventilation

Question 1

How do the bronchioles change shape to cause inspiration?

Answer 1

Bronchioles dilate, increasing the volume inside them an decreasing the pressure drawing air in.

Question 2

What proportions of chest expansion are caused by the diaphragm and by the Chest wall itself?

Answer 2

Diaphragm = 70%

Chest Wall = 30%

Question 3

During quiet breathing what muscles cause inhalation?

Answer 3

Diaphragm and External Intercostals

Question 4

During quiet breathing which muscles cause exhalation?

Answer 4

None

Question 5

To move to forced breathing which additional muscles aid with inhalation?

Answer 5

• Scalene
• Pec Minor
• Sternocleidomastoid
• Serratus Anterior

Question 6

During forced exhalation which muscles are in use?

Answer 6

• Internal and Innermost Intercostals

- Abdominal muscles

Question 7

What must oxygen diffuse to get from the alveolar lumen to the haemoglobin?

Answer 7

Alveolar epithelial cell -> Interstitial Fluid -> Endothelial Cell -> Plasma -> RBC membrane

Question 8

Define Tidal Volume

Answer 8

Amount of air displaced between normal inspiration and expiration, when extra effort is not applied

Question 9

Define Inspiratory Reserve Volume

Answer 9

Extra volume that can be breathed in when extra effort is applied

Question 10

Define residual volume

Answer 10

Volume left in the lungs at maximal expiration

Question 11

Define Vital Capacity

Answer 11

Amount of gas difference between maximal inspiration and and expiration (usually around 5L in healthy adults)

Question 12

Define respiratory capacity

Answer 12

The biggest breath that can be taken in from resting expiratory level

Question 13

What is the role of surfactant in terms of compliance and surface tension?

Answer 13

Increases compliance by reducing surface tension

Question 14

What is compliance?

Answer 14

The stretchiness of the lungs