Key learning points

1. Air enters through the mouth/nose, travels down the trachea and bronchi to the alveoli where gaseous exchange occurs.
2. Gaseous exchange is the process of diffusion where oxygen moves into the body and carbon dioxide moves out.
3. Diffusion is the movement of particles (e.g. oxygen) from an area of high to an area of low concentration.
4. Gaseous exchange increases during/immediately after exercise.

Keywords

• Trachea - the windpipe that connects the larynx (voice box) to the bronchi, allowing air to pass to and from the lungs

• Bronchi - two main branches off the trachea that lead to the lungs, where they further divide into bronchioles

• Alveoli - tiny air sacs in the lungs where gaseous exchange between air and blood takes place

• Gaseous exchange - the process where oxygen and carbon dioxide are switched between the lungs or the muscles and the bloodstream

• Diffusion - the movement of molecules from an area of higher concentration to an area of lower concentration

Common misconception