Key Points
Key Points: Mechanism of Respiration > Internal Respiration
- Meaning — O₂ from blood is delivered to cells/tissues, and CO₂ from cells passes into the blood.
- O₂ Transport — 97% as oxyhaemoglobin (HbO₂) via RBCs, 3% dissolved in plasma. One Hb molecule has 4 Fe²⁺ ions, each binding one O₂: Hb + 4O₂ → Hb(O₂)₄
- Bohr Effect — Rise in CO₂ / lower pH / higher temperature → reduces Hb-O₂ affinity (curve shifts right) → O₂ released to tissues.
- Haldane Effect — Binding of O₂ with Hb displaces CO₂ from blood (curve shifts left, higher Hb-O₂ affinity).
- CO₂ Transport — 70% as bicarbonate ions (HCO₃⁻) in plasma | 23% as carbaminohaemoglobin | 7% dissolved in plasma.
- Chloride Shift (Hamburger's Phenomenon) — When CO₂ enters blood, Cl⁻ moves into RBCs (Na⁺ stays behind). When CO₂ leaves, Cl⁻ moves back out. This alternate Cl⁻ movement maintains electrical balance.
