Adaptations of the alveoli

Question 1

Adaptation 1- Surface area

Answer 1

Large surface area- many alveoli are present in the lungs with a shape that further increases surface area.

Question 2

Adaptation 2- Walls

Answer 2

Thin walls- alveolar walls are one cell thick providing gases with a short diffusion distance.

Question 3

Adaptation 3- Walls

Answer 3

Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface.

Question 4

Adaptation 4- Walls

Answer 4

Permeable walls - allow gases to pass through.

Question 5

Adaptation 5- Blood supply

Answer 5

Extensive blood supply- ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.

Question 6

Adaptation 6- Diffusion gradient

Answer 6

A large diffusion gradient - breathing ensures that the oxygen concentration in the alveoli is higher than in the capillaries so oxygen moves from the alveoli to the blood. Carbon dioxide diffuses in the opposite direction.