BRAINCAKEThe Human Gas Exchange System
The human gas exchange system is inside the chest cavity (thorax). It carries air from outside the body to the lungs, where gas exchange takes place in the alveoli.
Air passes through these structures in order:
1. Nasal cavity: air is warmed, moistened and filtered by hairs and mucus.
2. Trachea (windpipe): a wide tube held open by C-shaped rings of cartilage, so it does not collapse when air pressure falls during breathing in. The rings are incomplete at the back, where the trachea lies against the oesophagus, so the oesophagus can expand when food is swallowed.
3. Bronchi: the trachea divides into two bronchi, one to each lung. They also have cartilage for support.
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More in Gas Exchange
- Surface Area to Volume Ratio
- Gas Exchange in Large Organisms
- Factors Affecting the Rate of Diffusion
- Effective Gas Exchange Systems
- Gas Exchange in the Alveoli
- Adaptations of the Human Gas Exchange System
- Breathing
- Inhalation
All 23 lessons in Gas Exchange · All Edexcel AS-level Biology topics