For instance, during this phase, erythrocytes normally lose all of their nuclear material, acquire their biconcave shape, and develop their final content of enzymes necessary for maintaining the biconcave shape and resisting destruction by oxidative stress. During maturation, their nuclear chromatin condenses, the glycogen content of the cytoplasm increases, and the surface properties governing the circulation, adherence, and migration to tissues are added. Monocytes and eosinophils follow similar developmental patterns. Platelets form from the cytoplasm of megakaryocytes, which are also derived from hematopoietic stem cells. Megakaryocytes undergo reduplication of their nuclear chromatin without cell division, leading to production of extremely large cells.
Platelets form from the breaking apart of the cytoplasm of the fully mature megakaryocytes.
When marrow damage occurs from chemotherapeutic agents and after hematopoietic transplantation, the megakaryocytes are often the slowest cells to recover and thrombocytopenia is often the last cytopenia to resolve. There are also important differences in the dynamics or kinetics of erythrocytes, platelets, and leukocytes in the blood. For instance, neutrophils turn over rapidly in the blood, with a blood half-life of six to eight hours, and essentially a new blood population of neutrophils is formed every 24 hours. These differences partially explain why neutrophils and their precursors are the predominant marrow cells, whereas erythrocytes far outnumber neutrophils in the blood. Similarly, the short half-life and high turnover rate of neutrophils explain why neutropenia is the most frequent hematologic consequence when bone marrow is damaged by drugs or radiation.