Bone marrow - nonneoplastic
Normal
Osteoblasts

Author: Dragos Luca, M.D. (see Authors page)

Revised: 6 July 2017, last major update September 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

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

Cite this page: Osteoblasts. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bonemarrowosteoblasts.html. Accessed August 17th, 2017.
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

Images hosted on other servers:

Interaction of osteoblasts and hematopoietic stem cells

Key functions and regulation of osteoblasts

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

Images hosted on PathOut server:

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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Osteoblasts

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