Which blood component is primarily responsible for carrying oxygen to tissues?

Which blood component is primarily responsible for carrying oxygen to tissues?

• A. Erythrocytes
• B. Leukocytes
• C. Platelets
• D. Hemoglobin

Answer: (D)

Oxygen transport in blood relies on a protein inside red blood cells that binds and carries oxygen to tissues. Hemoglobin is that protein. In the lungs, hemoglobin binds four oxygen molecules per molecule, forming oxyhemoglobin. As blood reaches tissues, conditions such as lower pH and higher CO2 lower hemoglobin’s affinity, releasing oxygen where needed. This binding greatly increases the blood’s oxygen-carrying capacity, since oxygen is not very soluble in plasma on its own. The red blood cell provides the carrier, but the actual molecule that binds and releases oxygen is hemoglobin. Leukocytes and platelets do not transport oxygen.

Oxygen transport in blood relies on a protein inside red blood cells that binds and carries oxygen to tissues. Hemoglobin is that protein. In the lungs, hemoglobin binds four oxygen molecules per molecule, forming oxyhemoglobin. As blood reaches tissues, conditions such as lower pH and higher CO2 lower hemoglobin’s affinity, releasing oxygen where needed. This binding greatly increases the blood’s oxygen-carrying capacity, since oxygen is not very soluble in plasma on its own. The red blood cell provides the carrier, but the actual molecule that binds and releases oxygen is hemoglobin. Leukocytes and platelets do not transport oxygen.