The blue rectangle in the upper figure indicates the region that will be analyzed in detail in the lower figure.
Observe in the lower figure:
1 – Zone of resting cartilage.
This Zone is adjacent to the bone of the epiphysis.
The bone is the reddish band in the uppermost region of the figure that does not become highlighted when using the mouse or clicking on the image. It can be recognized by the presence of osteocytes placed in a red/pink extracellular matrix (ECM).
The resting cartilage, on the other hand, has the appearance of a typical hyaline cartilage – it is formed by chondrocytes (highlighted in red after using the mouse or clicking) surrounded by a bluish ECM (highlighted in a darker tone of blue).
2 – Zone of serial cartilage. The chondrocytes of t zone (highlighted in red) actively divide by mitosis and become organized in rows, like stacks of coins. The cartilaginous matrix is highlighted in light blue.
How does longitudinal diaphysis growth occur?
Due to the proliferation of chondrocytes in the serial cartilage region, their daughter cells accumulate in the final (distal) portion of this region (opposite the resting cartilage region). The continuous accumulation of new chondrocytes “pushes” the epiphyses away from the diaphysis, resulting in longitudinal diaphysis growth.
