Chapter 15: Breathing and Exchange of Gases – Part 2
🌬️ Chapter 15: Breathing and Exchange of Gases – Part 2 🔄 Exchange of Gases and Transport of Oxygen 🔁 Gaseous Exchange: External and Internal Respiration 🫁 1. External Respiration (Pulmonary Gas Exchange) Takes place between the alveoli and blood capillaries . Oxygen from alveolar air diffuses into the blood. Carbon dioxide from blood diffuses into alveolar air. Both gases move by simple diffusion due to partial pressure gradients (ΔpO₂ and ΔpCO₂). Fun fact: Alveolar surface area is ~70 m² — almost like a tennis court! 🧬 2. Internal Respiration (Tissue Respiration) Occurs between blood capillaries and tissue cells . Oxygen moves from blood to tissues. Carbon dioxide moves from tissues to blood. Driven by differences in partial pressures: Tissue cells : Low pO₂, High pCO₂ Arterial blood : High pO₂, Low pCO₂ 📊 Partial Pressure (pO₂ and pCO₂) Location pO₂ (mm Hg) pCO₂ (mm Hg) Alveolar air 104 40 Oxygenated blood ...