Human gas exchange

Question 1

Features of alveoli to maximise rate of diffusion

Answer 1

1) alveolar epithelium= 1 cell thick so there’s a short diffusion path
2) large numbers of alveoli= large surface area
3) constant ventilation and good blood supply as there’s a steep concentration gradient of o2 and co2

Question 2

Capillaries are blood vessels with a one-cell thick layer of …

Answer 2

endothelial cells

Question 3

During gas exchange in the lungs, oxygen and carbon dioxide move between the alveolus and the capillary by diffusing down …

Answer 3

concentration gradients

Question 4

How is a steep concentration gradient of oxygen and carbon dioxide maintained between the alveoli and capillaries?

Answer 4

There is a constant ventilation and good blood supply