人体及动物的外周血细胞是处于不断地破坏和不断地补充的动力平衡过程,维持这一过程的细胞来源是骨髓造血干细胞库。在正常情况下,造血干细胞库的细胞群,在数量上保持恒定状态。当机体需要较多血细胞供应时,造血干细胞库的多向性干细胞,或称 CFU-S(Sp-leen colony forming unit),就开始增殖,当一个干细胞分裂为二个子细胞时,其中一个子 Human and animal peripheral blood cells are constantly undermining and constantly replenishing the dynamic balance of the process, the source of cells to maintain this process is a bone marrow hematopoietic stem cell bank. Under normal conditions, the population of hematopoietic stem cell stocks remains constant in number. When the body needs more blood supply, multipotential stem cells from the hematopoietic stem cell bank, or CFU-S, begin to proliferate. When a stem cell divides into two daughter cells, one of the two