The lungs

• The lungs are in the thorax
• Lungs are protected by ribcage
• Air that you breathe in goes through the trachea which splits into 2 tubes called bronchi (one goes to each lung)
• Bronchi split into smaller tubes called bronchioles which end at small bags called alveoli
• The lungs contain millions and millions of air sacs called alveoli surrounded by a network of blood capillaries - this is where gas exchange happens
• Alveoli have thin walls so gases can diffuse easily across them