1:5:1 Respiratory system

Question 1

List any characteristics of any exchange surface

Answer 1

Large surface area
Thin walls
Moist walls
Permeable
Good blood supply
Diffusion gradient

Question 2

Explain the adaptations of respiratory surfaces in plants and animals.

Answer 2

Large surface area - numerous alveoli - larger area for more diffusion

Thin walls - alveoli one cell thick - short diffusion distance

Moist walls - mucus - gases dissolve in moisture to speed up diffusion

Permeable - moist thin walls of alveoli - allow gases to diffuse through

Good blood supply - numerous capillaries around alveoli - moves oxygen to the cells, brings CO2 to the lungs

Diffusion gradient -maintained by breathing - large diffusion gradient, breathing maintains a high level of oxygen in the alveoli therefore oxygen diffuses into the blood