Oxygen Transport

Oxygen transport refers to the physiological process by which oxygen is carried from the lungs to tissues throughout the body, primarily via the blood. This process is essential for cellular respiration and energy production in all aerobic organisms. The vast majority of oxygen is transported in blood bound reversibly to hemoglobin, a protein found within red blood cells (erythrocytes). A small fraction of oxygen is dissolved directly in plasma and red cell water. Oxygen binding to hemoglobin exhibits cooperativity: as one molecule binds, hemoglobin’s affinity for additional oxygen increases. The affinity of hemoglobin for oxygen changes depending on local conditions such as partial pressure of O₂, temperature, CO₂ levels, pH, and 2,3-DPG concentration. Red blood cells are highly specialized for efficient gas transport. Adequate tissue delivery depends on both sufficient red cell mass/hemoglobin concentration and proper cardiovascular function. Disruptions can lead to hypoxia or anemia-related symptoms. Red cells also play roles in carbon dioxide transport back from tissues.