Before learning to examine bone marrow microscopically, it is important to understand the basic structure and function of the bone marrow.
The bone marrow is one of the largest organs in the body. The normal adult marrow on a daily basis produces approximately 2.5 billion red cells, 2.5 billion platelets and 1.5 billion granulocytes per kilogram of body weight. The main function of this organ is the formation and development of blood cells. Hematopoiesis begins in the yolk sac in the first weeks of embryonic life; stem cells from the yolk sac travel first to the liver and then to the spleen. These organs are the only blood forming sites during the first three months of fetal life. At the beginning of the fourth month the bone marrow begins its life-long function of cell production.
