Gaseous exchange means the diffusion of oxygen, carbon dioxide, water and other materials takes place. The oxygen diffuses through the membrane of the alveoli in to the capillaries and carbon dioxide diffuse from the capillaries into the alveoli where it is expelled from the body when expiring.
When Gaseous exchange occurs the gases only have to diffuse through two cells. These are the epithelial cell of the alveoli and the capillary wall.
In order to succeed with effective gaseous exchange a number of conditions must be met, these are
large surface area and thin walls which allow the diffusion rate of the gases to be much faster,if there is a lot of alveoli within the lungs then more gaseous exchange can occur (The alveoli can increase through exercise)
Water being diffused by surrounding calls keep the alveoli walls moist to allow effective gas exchange.
Faster diffusion rate between blood and alveoli will normally occur when the right temperature is met because it is more effective in warmer conditions.
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