Alveoli and Gas Exchange in the Lungs

Jun 13, 2024

Alveoli and Gas Exchange in the Lungs

Structure of Alveoli

  • Location: End of the bronchioles
  • Shape: Resembles cauliflower; tiny air sacs
  • Diagram Insight: Oxygen and carbon dioxide are supplied and removed through breathing

Gas Exchange Process

  • Lining: One cell thick
    • Oxygen diffuses across the cell membrane lining the alveolus
    • Continues to diffuse across the blood capillary lining
    • Finally, diffuses into red blood cells and binds with hemoglobin to form oxyhemoglobin
    • Carbon dioxide follows the reverse path to exit the body
  • Concentration Gradient: Maintained by constant supply and removal of gases through breathing and blood flow

Features of Gas Exchange Surface

  1. Large Surface Area:
  • Provided by shape and number of alveoli
  1. Thinness:
  • Only one cell thick, short diffusion pathway
  1. Moist Lining:
  • Allows gases to dissolve and diffuse across the lining
  1. Good Blood Supply:
  • Dense network of blood capillaries around each alveolus

Microscopic View of Lung Tissue

  • Capillary Network: Zigzag crisscross mesh
  • Red Blood Cells: Visible as individual red splotches

Ventilation

  • Good Air Supply:
    • Ensured through effective breathing

Exam Tips

  • **Features for Efficient Gas Exchange: **
    • Large surface area from numerous alveoli
    • One cell thick surface for short diffusion pathway
    • Dense capillary network supplying blood