Medullary hematopoiesis

Production of blood cells in bone marrow of the central axial skeleton is referred to as medullary hematopoiesis. Hematopoietic tissue in adult bone marrow is well perfused and contains fat cells (adipocytes), and various types of blood and blood precursor cells encased within a protein matrix. Fibroblast, stromal and endothelial cells within bone marrow, serve as sources of matrix proteins as well as a factory for growth factors and chemokines that regulate blood cell production and release matured cells into the circulation [2,3]. Chemokines act as signal lamps for trafficking of lymphocytes in and out of lymphoid tissues. Erythroblasts, neutrophils, lymphoblasts, macrophages, megakaryocytes, and pluripotent stem cells are also found within the calcihed lattice crisscrossing the marrow space. 

Problems can come about if due to technical difficulties a second blood sample has to be taken within a short period after the first, failing withdrawal. In a small rodent the loss of blood is counteracted by rapid erythropoesis in the bone marrow, and the spleen. During the histopathological evaluation increased erythropoesis is seen in the bone marrow and the spleen (extra-medullary hematopoiesis). 

Knobel, B., Melamud, E., Virag, L, Meytes, D. Ectopic medullary hematopoiesis as a cause of ascites in agnogenic myeloid metaplasia. Case report and review of the literature. Acta Haematol. 1993 89 ... 

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See also in sourсe #XX -- [ ]

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