Ventilation

Question 1

What is pulmonary ventilation?

Answer 1

• Means related to the lungs
• Inspiration- air in
• Expiration- air out
• Mechanical forces cause the movement of air
• Flow from higher to lower pressure

Question 2

How does inspiration work?

Answer 2

1. External intercostal and diaphragm muscles contracts
   - Causes ribcage to move upwards and outwards
   - diaphragm flatterns
2. Volume of thorax has now increased
   - This decreases the lung pressure compared to atmospheric pressure
3. The air then flows into the lungs
   - Inspiration is an active process
   - Requires energy

Question 3

How does expiration work?

Answer 3

1. External intercostal and diaphragm muscles relax
   - Causes ribcage to move downwards and inwards due to impact of gravity
   - diaphragm curves due to abdominal muscles pushing back up
2. Volume of thorax has now decreased
   - This increases the lung pressure compared to atmospheric pressure
3. The air is forced out of the lungs
   - Expiration is an passive process
   - Does not requires energy

Question 4

Forced Expiration

Answer 4

• The internal intercostal muscles contract
• Thorax further decreases in volume
• Pulls ribcage down and in
• Not passive process

Question 5

How do u measure lung function?

Answer 5

Pulmonary Ventilation = Tidal Volume X Ventilation Rate