Lungs
Lungs are organs used by animals for respiration. Gas is exchanged with the air: oxygen goes in and carbon dioxide goes out.
Upper airways are lined with mucus and cilia to remove debris and defend against infection.
Lungs can collapse.
Route[edit]
- Trachea - windpipe
- Bronchi
- Bronchioles
- Alveoli - tiny air-filled sacs with moist linings where gas exchange takes place
- Surfactant prevents alveoli from collapsing due to surface tension of water. Premature babies sometimes lack surfactant.