Final answer:
Erythrocytes, or red blood cells, have a natural lifespan of roughly 120 days in the bloodstream before being removed and recycled by macrophages, primarily in the spleen, liver, and bone marrow.
Step-by-step explanation:
The maximum lifespan of an erythrocyte, commonly known as a red blood cell, is about 120 days. Throughout their lifecycle, erythrocytes circulate in the bloodstream and eventually, aged cells are phagocytized by macrophages in the reticuloendothelial system, particularly in the spleen, liver, and bone marrow. The components of erythrocytes, including hemoglobin, are then recycled. In conditions such as sickle cell anemia, the lifespan of erythrocytes is significantly reduced due to instability of hemoglobin (HbS), leading to a lifespan closer to 30 days, which causes anemia and other symptoms.