Changes in the bone matrix formation due to age

Abstract

Changes in the fine structures in the surface of the bony palate in the Wistar rat during the developing period were investigated under a scanning electron microscope.The results were as follows:
The surface of the bony palate of 1-4 week-old rats shows a large number of roundish blood vessel holes of 30-100μ in diameter opening into it, and many comparatively shallow-bottomed osteocyte lacunae are scattered in the walls of the roundish blood vessel holes and in the matrix of their peripheries.The matrix around the blood vessel holes is conspicuous and it is shown that the matrix covers the blood vessel holes from their circumferences. The considerable matrix formation is observed in the surface of the bony palate, therefore the diameters of the blood vessel holes become smaller and the center of the matrix around the blood vessel holes is swelled by the newly formed matrix.
At 7 weeks after birth, the surface of the bony palate is dotted with roundish blood vessel holes of about 50μ and 20μ in diameter, the inner walls of which are formed of ring-shaped collagen fiber bundles, and there are scarcely osteocyte lacunae in their walls.
From 8 weeks after birth, the diameters of the blood vessel holes become still narrower, and the blood vessel holes are almost closed at 15 weeks after birth.