Gas Exchange in the Alveoli

Question 1

how does gas exchange happen in the alveoli?

Answer 1

• oxygen diffuses from the air into the red blood cells, where it binds with the haemoglobin for transport
• carbon dioxide, dissolved in the plasma, diffuses from the blood into the alveolus

Question 2

how is the alveoli adapted for diffusion?

Answer 2

• large surface area - increases rate of diffusion
• capillary network of capillaries (carries deoxygenated blood to the alveolus and move oxygenated blood away) - maintains a high concentration gradient
• one cell thick walls - small diffusion distance