gas exchange in the alveoli

Question 1

what happens to oxygen in the alveoli?

Answer 1

oxygen diffuses from the air into the red blood cells, where it binds with the haemoglobin for transport

Question 2

what happens to carbon dioxide in the alveoli?

Answer 2

carbon dioxide, dissolved in the plasma, diffuses from the blood into the alveolus

Question 3

air leaving the lungs contains more or less oxygen?

Answer 3

about 4% less oxygen and 4% more carbon dioxide than the air that entered the lungs

Question 4

what is the approximate surface area in the lungs?

Answer 4

60m2

Question 5

what is each alveolus surrounded by?

Answer 5

a network of capillaries

Question 6

what do the capillaries carry?

Answer 6

• deoxygenated blood to the alveolus
• more oxygenated blood away

Question 7

the capillaries carrying 2 different types of blood means what for the concentration gradient?

Answer 7

maintains a high concentration gradient and so therefore speeds up diffusion

Question 8

the walls of the alveoli being only one cell thick and being immediately next to the next alveoli means?

Answer 8

the gases only need to move a very small distance, speeding up diffusion