What is the average lifespan of a red blood cell (RBC)?

The average lifespan of a red blood cell (RBC) is approximately 120 days. This lifespan is determined by the process of erythropoiesis, which occurs in the bone marrow, where RBCs are produced. Once mature, red blood cells are released into the bloodstream, where they have the critical role of transporting oxygen from the lungs to the tissues and returning carbon dioxide from the tissues back to the lungs.

After about 120 days, RBCs become less functional and are typically removed from circulation by the spleen and liver, where they are broken down. This lifespan is vital for maintaining a stable and effective supply of healthy red blood cells in the body. Understanding the average lifespan of RBCs is important in clinical settings, especially when evaluating conditions such as anemia, blood loss, or disorders affecting the production of erythrocytes.

In this context, other options like 30 days, 60 days, and 180 days do not align with the established lifespan of red blood cells. Notably, 30 days and 60 days are significantly shorter than the actual lifespan, suggesting an incorrect understanding of RBC longevity, while 180 days exceeds the average lifespan, which could indicate misconceptions about the lifespan of cellular components in the blood.