Structure of the Respiratory System (OCR GCSE Physical Education (PE)): Revision Note

The pathway of air

• Oxygen from the air we breathe is transported through a system of tubes in our lungs and then diffuses into the bloodstream

• The pathway taken by air during breathing is:

  mouth/nose → trachea → bronchi → bronchioles → alveoli

  • Mouth/nose

    • Air enters the body and is warmed as it travels through the mouth and nose

  • Trachea

    • It then enters the trachea

    • This is lined with ciliated cells to trap dust

    • Rings of cartilage within the walls of the trachea ensure that it remains open to allow air movement

    • The trachea divides into two bronchi

  • Bronchi (singular bronchus)

    • A pair of smaller tubes that branch from the trachea, allowing air to travel between the trachea and the lungs

  • Bronchioles

    • Smaller tubes that branch from the bronchi enabling the air to pass into the alveoli

  • Alveoli

    • Tiny air sacs located at the end of the bronchioles

    • These are where gaseous exchange takes place

    • Surrounded by a network of capillaries