A section of bone may fool the observer and induce him to think that it is a section of cartilage. One big difference is the presence between the cells of a homogeneous acidophilic area that stains in pink in sections stained by hematoxylin and eosin). The extracellular matrix of the cartilage stains in different shades of blue with HE.
There are two lineages of cells in bone tissue: the osteoblastic lineage and the osteoclastic lineage.
The osteoblastic lineage is composed of three cell types: osteoprogenitor cells, osteoblasts, and osteocytes. Osteoblasts and osteocytes are easily recognizable in histological sections, but not the osteoprogenitor cells.The osteoclasts result from the fusion of cells of monocyte precursors.
Lower figure
Observe bone cells
1 – Osteoblasts and other bone cells covering the surface of a bone lamella (in orange after clicking). Oteoblasts are the majority of the cells covering bone.
2 – Osteocytes are located inside the bone, surrounded by a pink stained extracellular matrix. They are highlighted in green. Two osteocytes (highlighted in dark green) are very close to the surface of the trabecula and possibly are two osteocytes that recently became surrounded by bone matrix, transitioning from osteoblast to osteocyte.
3 – Observe an osteoclast on the outer surface of a trabecula (highlighted in dark blue).It is a very large cell with a strong stained cytoplasm. One key feature is the presence of several nuclei in their cytoplasm.
