造血干细胞是存在于造血组织中的一群原始造血细胞。它具有自我增殖能力,并能通过增殖分化产生各种功能不同的子代细胞,因此造血干细胞又称为多能造血干细胞(Pluripotent hemopoietic stem cell)。造血干细胞在人胚二周时出现在卵黄囊,第四周开始转移到胚肝,妊娠五个月 Hematopoietic stem cells are a group of primitive hematopoietic cells present in hematopoietic tissues. It has the ability to self-proliferation, and can produce a variety of different progeny cells through proliferation and differentiation, so hematopoietic stem cells, also known as pluripotent hemopoietic stem cells. Hematopoietic stem cells appear in the yolk sac two weeks in human embryos, the first four weeks of transfer to embryo liver, five months of pregnancy