Biology 4.1 Structure of the Human Gas-Exchange System

Lungs act as an interface for exchange of gases.

Aerobic organisms require constant supply of oxygen to release energy as ATP. 

Carbon dioxide needs to be removed.

Volume of oxygen absorbed and volume of CO2 removed = large in mammals because:

• They are relatively large organisms with large volume of living cells.
• Maintain a high body temperature - have high metabolic and respiratory rates.

Mammals have evolved specialised exchange surfaces, lungs, for effecient gas exchange between air and blood.

Mammalian lungs

Located inside the body because:

• air is not dense enough to support and protect the delicate structures.
• would lose water otherwise and dry out.

Lungs are supported and protect by rib cage.

Ribs moved by muscles between them…