chap 9: respiration

Question 1

adaptations of the lungs for efficient gas exchange (4)

Answer 1

1. numerous alveoli in the lungs to provide a large surface area to volume ratio for efficient gas exchange
2. walls of the alveolus are only one cell thick to provide a shorter diffusion distance for the gases, ensuring a faster rate of diffusion
3. thin film of moisture covers the surface of the alveolus to allow oxygen to dissolve in it
4. inner surface walls of the alveoli are richly supplied with blood capillaries as the flow of blood maintains the concentration gradient of gases