Bone tissue - details

In this final magnification, we see the details of an osteon.

Notice the intricate network of fibers radiating radially from the Haversian canal and all the small black "dots" scattered throughout the tissue.

The osteocytes in their almond-shaped lacunae appear as tiny grains within the extracellular matrix (bone matrix). From these, small black "threads" radiate outward. These are canaliculi—tiny channels that extend perpendicularly from the lacunae and connect with neighboring canaliculi and Haversian canals.

Through this canal system, osteocytes can exchange substances. This system is both essential and ingenious, as the calcification of the extracellular matrix makes diffusion through it impossible.

There’s much more to say about bone tissue, but we’ve covered the most important structures observable under a light microscope.

Be sure to check out the EM images!