Histology Photomicrographs

Human Anatomy and Physiology (BIOL& 241L-242L)
Karen Hart, Peninsula College

Cartilage and bone: Compact bone


Compact bone forms the surface of all bones. The bone of the shaft of a long bone is a thick layer of compact bone.

Slide: Bone, ground, c.s. (cross section) HB 8-4 or H780

Microscope at 400X

The outlined area is a cross section of an osteon of compact bone. In three dimensions an osteon is cylindrical in shape.

In the center of each osteon is the central canal, a space that houses blood vessels and nerves that supply bone. Concentric layers of bone cells (osteocytes) and bone matrix surround the central canal.

Osteocytes occupy spaces (lacunae) in the bone matrix. Osteocytes maintain the bone matrix. Osteocytes at an earlier stage of development (when they were called osteoblasts) formed the bone matrix.

Osteocytes have long processes that extend out to touch neighboring osteocytes. The processes of osteocytes near the central canal also extend to the central canal. Osteocyte processes lie in tiny canals (canaliculi) in the bone matrix. Canaliculi allow the passage of interstitial fluid between the central canal and the lacunae housing osteocytes.

cc = central canal

la = lacuna

Canaliculi appear as tiny dark lines but are too small to be seen clearly.

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