1.2.2 Gas exchange

Question 1

How does oxygen get into the blood?

Answer 1

Gases such as oxygen cross the walls of the alveoli into the blood system by diffusion

Question 2

What does gas exchange need to be, and how is this made possible?

Answer 2

Gas exchange needs to be rapid to meet demand. The fine structure of the lungs helps to maximize this.

Question 3

What does the alveoli have that helps make gas exchange more efficient?

Answer 3

The alveoli provide a large surface area for gas exchange.

Question 4

What is the rate of diffusion dependent on?

Answer 4

• Surface area
• Concentration gradient
• Thickness of surface

Question 5

What is Fick’s law?

Answer 5

rate of diffusion = surface area X difference in concentration / thickness of surface

Question 6

How do the lungs allow for rapid diffusion?

Answer 6

• Large surface area
• Steep concentration gradient
• Thin walls of alveoil and capillaries

Question 7

What can the mucus in the bronchioles of a person with CF do?

Answer 7

The sticky mucus layer in the bronchioles of a person with CF can block the narrow airways. This blocks ventilation of the alveoli, reducing surface area.

Question 8

When may a person with CF become short of breath?

Answer 8

People with CF become short of breath when taking part in physical activity