The Journey of Red and White Blood Cells and Platelets After the End of Their Lifespan

The bone marrow produces millions of new blood cells every second, but their total number remains approximately constant. So where do old red blood cells, white blood cells, and platelets go? According to scientists, each type of blood cell has a specific lifespan. Red blood cells, or erythrocytes, are the longest-lived blood cells, surviving for about 120 days. The lifespan of white blood cells, or leukocytes, varies by type: granulocytes and monocytes live between 4 and 5 days up to 20 days, while lymphocytes can live for 100 to 200 days. Platelets, or thrombocytes, have a short lifespan, ranging from 3 to 5 days. Most blood cells are destroyed in the spleen and liver. When they die in tissues, they are engulfed and digested by specialized immune system cells called macrophages. Healthy red blood cells have a flexible membrane that allows them to easily pass through the narrow pores in the soft blood vessels of the spleen by changing their shape. However, as they approach the end of their life cycle, the red blood cell membrane loses its flexibility, making them unable to penetrate the capillaries. Consequently, these cells are filtered out in the spleen and engulfed by the reticuloendothelial system cells (macrophages). For this reason, the spleen is considered the “graveyard of red blood cells.” When red blood cells break down in the liver, the pigment bilirubin is formed. This pigment enters the intestines with bile. Source: health.mail.ru