B2 - Breathing and Gas Exchange

Question 1

Where is alveoli found?

Answer 1

On the end of bronchioles inside of the lungs

Question 2

How is an alveolus adapted for gas exchange?

Answer 2

• One cell thick - short diffusion pathway, increases the rate at which CO2 and O2 can diffuse across
• Very large surface area (folded)
• Moist walls to allow casses to dissolve and increases the rate of diffusion
• Surrounded by capillaries - maintains a steep concentration graident for CO2 and O2

Question 3

Explain the process of breathing in the alveolus

Answer 3

1. We breathe in oxygen and a small amount of carbon dioxide
2. The oxygen diffuses from the alveoli into the surrounding capillaries. The oxygen binds to the haemoglobin, oxygenating them so they can transport oxygen around the body
3. CO2 is dissolved in plasma and diffuses into the alveoli and is exhaled

Question 4

Components in the respiratory system

Answer 4

• Nose
• Mouth
• Trachea
• Intercostal muscles
• Bronchi
• Bronchioles
• Ribs
• Lungs
• Alveoli
• Abdomen
• Diaphragm
• Heart