Sauerstofftransports

Sauerstofftransports refers to the physiological process of delivering oxygen from the lungs to tissues throughout the body. The system relies primarily on hemoglobin in red blood cells and, to a lesser extent, the dissolved oxygen in plasma. Myoglobin in muscles serves as an oxygen reserve and facilitates diffusion in tissue.

Oxygen loading occurs in the lungs where alveolar PO2 is high, promoting binding of O2 to hemoglobin to form oxyhemoglobin. Unloading occurs in tissues where PO2 is low and carbon dioxide, acidity, heat, and 2,3-bisphosphoglycerate decrease Hb’s affinity for oxygen (the Bohr effect; the Haldane effect describes CO2 transport influences on oxygen binding). About 98–100% of arterial O2 is bound to hemoglobin under normal conditions; 2–4 mL O2 per 100 mL remains dissolved in plasma, which is the portion available for immediate diffusion.

The oxygen content delivered to tissues (DO2) depends on cardiac output and the arterial oxygen content (CaO2), and is reflected by the arterial–venous O2 difference. Hemoglobin’s four binding sites per molecule allow transport of up to four oxygen molecules per hemoglobin, with saturation measured as the percent of sites occupied.

Clinical relevance includes hypoxemia, anemia, and polycythemia, which alter DO2; high altitude reduces arterial PO2; carbon monoxide and methemoglobinemia impair oxygen transport by altering Hb binding. Understanding Sauerstofftransports involves physiology of diffusion, gas exchange, and circulatory regulation.