Hematopoiesis Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Hematopoiesis and links to relevant pages within the course.
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| Sites of active hematopoiesis in the adult are: | View Page |
| Basic Structure and Function of Bone Marrow 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. | View Page |
| Basic Structure and Function of Bone Marrow Cont'd The liver is the primary blood-forming organ until the sixth gestational month: then the bone marrow becomes the primary production site. At birth nearly all the bones are actively involved in cell production. By age four, hematopoiesis decreases in the shaft of the long bones and fat cells begin to be visible. At age 18 and throughout adult life the active cell producing sites are:skullscapulasternumribsvertabraepelvisThe long bones, tibia and femur, are active bone marrow sites from birth into the second decade.
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| Representative Counting Field The actual cell count is performed using the oil (100x) objective. This oil immersion field shows a representative counting field. Four granulocytes, a prorubricyte, and two rubricytes are completely visible here. 100 to 500 nucleated cells are generally counted,depending on the cellularity of the smear, and only cells completely visible in the field should be included in the count. | View Page |
| The nucleated red blood cell and myelocyte photographed here were found on scanning of a peripheral blood smear. In context they are suggestive of metastatic carcinoma to the bone marrow. | View Page |
| Conditions suggested by the macrocytes and the neutrophil in the photograph to the right include: | View Page |
| The presence in the peripheral blood of an increased number of hypersegmented white blood cells as presented in the photograph serves as a marker for preleukemia. | View Page |