Lungs (1)

• Lung primary function


  • O2 is essential requirement for normal cell metabolism, CO2 is a major waste product
  • Transport O2 to cells and CO2 to lungs for excretion
• Lung secondary functions


  • Water loss, heat elimination, large surface area for gas exchange
  • Enhances venous return
• Air passage


  1. Nose

  2. Pharynx

  3. Larynx

  4. Trachea

  5. Bronchial tree

  6. Lungs
• Airways


  • Divided into generations getting smaller (increasing SA)
  • Conducting zone is the larynx to the terminal bronchioles
  • Respiratory zone is the respiratory bronchioles and alveolar sacs
• Bronchi branching


  1. Primary bronchi

  2. Secondary bronchi

  3. Tertiary, segmental bronchi

  4. Multiple and terminal bronchioles