Gas exchange takes place in the lungs between the alveoli and the capillaries that surround them. Oxygen is breathed in and passed into the circulatory system. The blood containing oxygen is oxygenated. Carbon dioxide is passed from the blood into the lungs. Blood carrying carbon dioxide is deoxygenated.
This process is essential for respiration. Respiration provides the energy vital for all functions in the body. If you look at the structure of the alveoli you will see that these small highly folded structures are well designed for gas exchange.
There are three factors that are important for efficient gas exchange
• Surface area(the more area for exchange, the more exchange can take place)
• Concentration of gas (the more gas, the more gas exchange)
• Thickness of surface (less distance for gas to travel, then more gas exchange)
This can be summarised in Ficks Law:
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