Bone marrow nonneoplastic



Topic Completed: 1 September 2012

Minor changes: 14 May 2021

Copyright: 2002-2021,, Inc.

PubMed Search: Bone marrow [title] osteoblasts [title]

Dragos C. Luca, M.D.
Page views in 2020: 1,508
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Cite this page: Luca DC. Osteoblasts. website. Accessed November 27th, 2021.
Definition / general
  • Bone forming cell that arises from marrow mesenchymal (stromal) cells, unlike osteoclasts which are of hematopoietic origin
  • Along endosteal surface of bony trabeculae or along margins in marrow smears
  • Common in children; in adults associated with various diseases and healing biopsy sites
  • Synthesize angiopoietin and osteopontin, which inhibit hematopoietic stem cell proliferation (Br J Haematol 2006;134:467, J Clin Invest 2006;116:1195)
  • Synthesize and transport collagenous matrix, initiate and regulate mineralization, control removal of bone via osteoclasts
  • When active are plump and present on bone surface; eventually are encased within the collagen they produce and get flattened (and become osteocytes)
  • Activity is promoted by physical activity (Wolff's law of bone adaptation)
  • Express parathormone receptors (mediates the activation of osteoclasts) and vitamin D receptor
  • Control osteoclast activity via parathyroid hormone (parathormone), PHRP (parathyroid hormone related protein), IL1 and TNF alpha
  • Digestion of bone by osteoclasts releases cytokines and growth factors for osteoblasts
Diagrams / tables

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Interaction of osteoblasts and hematopoietic stem cells

Microscopic (histologic) description
  • Large (25 - 50 microns), often oval with abundant blue gray cytoplasm and perinuclear hof separated from the nucleus (unlike plasma cells)
  • Nucleus is markedly eccentric and round / ovoid with one or more nucleoli
Microscopic (histologic) images

AFIP images

Osteoblasts in marrow smear are twice as big as
plasma cells, have abundant blue cytoplasm,
eccentric nucleus and often single nucleolus

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Positive stains
Negative stains
Electron microscopy description
  • Resemble fibroblasts due to well developed rough endoplasmic reticulum and Golgi zone
Electron microscopy images

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Colorized SEM

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