Describe how the lungs are adapted for gas exchange (6 marks)

-There are a large number of alveoli, increasing the surface area available for gas exchange. The alveoli have many infoldings, further increasing the surface area.- The walls of the alveoli are thin, they are one cell thick. This reduces the diffusion distance for gases, increasing the rate of gas exchange.- The alveoli are surrounded by a dense capillary network. This means gases diffuse into the blood, where they are rapidly removed from the alveoli, helping to maintain a concentration gradient for the diffusion of gases.- The alveoli are moist, which also aids the diffusion of gases.Key themes; large surface area, short diffusion distance, moist surfaces, capillary network