Understanding Red Blood Cells and Their Functions

9. Red Blood Cell Death

On average, red blood cells have a lifetime of between 100 and 120 days. Over time, red blood cells undergo changes that allow macrophages from the bone marrow, liver, and spleen to remove them. The body breaks down the red blood cells and recycles their various components. Globin, the protein portion of hemoglobin, breaks down into amino acids, which may travel to the bone marrow for use in the production of new erythrocytes. The body stores iron in the liver or spleen, though it may also send it to the bone marrow for erythropoiesis. Non-iron portions degrade into biliverdin and then bilirubin, which the liver uses to manufacture bile.