Lung and Respiratory System

Question 1

How does air move in and out of the lungs?

Answer 1

The air that you breath in goes through the trachea.

Then it passes through the bronchi, then the bronchioles and ends up in the alveoli.

Question 2

How do alveoli carry out gas exchange?

Answer 2

Alveoli are surrounded by blood capillaries.

• Blood comes into the lungs through the capillaries - contains lots of CO2 and little oxygen.
• Oxygen diffuses out of the air in the alveolus (higher concentration) into the blood (lower concentration).
• CO2 diffuses out of the blood (higher concentration) into the air in the alveolus (lower concentration).
• Blood leaves the lungs and travels around the body.