Bone Marrow

The biogenesis of the different blood cells in the bone marrow (medulla ossium) of adults occurs simultaneously and in close spatial proximity. The number of precursor cells accounts for the variability in form and character of cells in the bone marrow. Numerous capillaries are present in the reticular connective tissue stroma. They are enlarge d to sinusoids and measure about 50–70 μm. In the reticular spaces occur mostly myeloid progenitor cells, but also macrophages and local adipocytes. They form the marrow parenchyme . This figure  shows a section of the human bone marrow (iliac crest). The eosinophilic promyelocytes 1 are particularly easy to recognize. However, a more precise description of the different cell types requires higher microscopic resolution.

1 Eosinophilic promyelocyte

2 Neutrophilic promyelocyte

3 Proerythroblast

4 Adipocytes

Stain: Pappenheim (May -Grünwald, Giemsa); magnification: × 320

References

Kuehnel, W.(2003). Color Atlas of Cytology, Histology, and Microscopic Anatomy. 4^th edition . Institute of Anatomy Universitätzu Luebeck Luebeck, Germany . Thieme Stuttgart · New York .