humans

• humans need to get oxygen into blood (for respiration) and they need to get rid of carbon dioxide (made by respiring cells)
• humans breathe to get oxygen into the body and remove carbon dioxide
• 1. as you breathe in, air enters the trachea (windpipe)
• 2. the trachea splits into two bronchi - one bronchus leading to each lung
• 3. each bronchus then branches off into smaller tubes - bronchioles
• 4. the bronchioles end in small 'air sacs' called alveoli, where gases are exchanged
• 5. the ribcage, intercostal muscles and diaphragm all work together to move air in and out