Pathway of air to the body

• The nose has a much more important role than smelling
• Nose


  First organ in the respiratory system where air passes through
• Nasal septum


  • Divides the left and right nasal passages
  • Separates the nostrils
• Respiratory tract

  • Lined with a mucous membrane
  • Composed primarily of epithelial cells
• Cilia


  • Microscopic fingerlike extensions that fringe each epithelial cell
• Coarse hairs in nostrils


  • Help trap and prevent dirt and large particles from entering the respiratory tract
• Nasal passages


  Where air is moistened and warmed
• Air passage through the respiratory system

  1. Nose

  2. Pharynx

  3. Larynx

  4. Trachea

  5. Bronchi

  6. Bronchioles

  7. Alveoli
• Larynx


  Voice box with ligaments called vocal cords that vibrate to create sounds
• Trachea


  Tube made up of cartilage that carries air toward the lungs
• Bronchi


  • Two branches of the lungs
  • Lead to bronchioles
• Bronchioles


  • Microscopic tubes that branch out into alveoli
• Alveoli


  Sites of gas exchange
• Each lung has about 300 million alveoli