Question

How are oxygen and carbon dioxide transported in human beings? How are lungs designed to maximise the area for exchange of gases?

Answer 1

1. In lungs, each bronchi branches out into smaller tubes called bronchioles.
2. At the other end of these bronchioles, many small sac-like structures are present called alveoli.
3. These alveoli are surrounded by blood vessels (capillaries).
4. The blood absorb oxygen present into air from alveoli which is inhaled, this blood is called oxygenated blood or pure blood.
5. The carbon dioxide present into blood diffuses out into the alveoli and is expelled out from the body when exhaled.
6. Thus, during breathing exchange of oxygen and carbon dioxide takes place in the lungs.
7. There are many alveoli are present that maximize the area of lungs for exchange of gases.