6.8 Exchange of gases in the lungs

Question 1

Adaptations that make alveoli exchange gases rapidly

Answer 1

• r.b.c. are flattened against wall of capillaries
• walls of alveoli and capillaries are thin
• r.b.c. are slowed
• constant ventilation
• constant bloodflow through pulmonary capillaries
• many alveoli and capillaries

Question 2

What does r.b.c. being flattened against wall of capillaries cause?

Answer 2

It reduces the distance between alveolar air and red blood cells
Causing a short diffusion pathway

Question 3

What does r.b.c. being slowed cause?

Answer 3

More time for diffusion = more diffusion

Question 4

What does constant ventilation and constant heartbeat cause?

Answer 4

A steep gradient between alveoli and capillaries
Maintains conc. grad. = constant diffusion

Question 5

What does many alveoli and capillaries cause?

Answer 5

Large surface area = more diffusion can take place