Which statement best defines interstitial growth?

Which statement best defines interstitial growth?

• A. Lengthening from the inside to grow
• B. Thickening from the outside to grow
• C. Growth due to periosteum
• D. Calcification of cartilage

Answer: (A)

Interstitial growth is growth from within the tissue. In cartilage, chondrocytes inside lacunae divide and produce new matrix, causing the tissue to expand from the inside and lengthen. This internal, internal-expansion mechanism is what drives length growth. The other ideas describe growth that occurs at the surface (appositional growth), which adds layers and makes tissue thicker rather than longer. Growth involving periosteum relates to bone thickening, not internal cartilage lengthening. Calcification of cartilage is mineral deposition that stiffens tissue and does not constitute growth.

Interstitial growth is growth from within the tissue. In cartilage, chondrocytes inside lacunae divide and produce new matrix, causing the tissue to expand from the inside and lengthen. This internal, internal-expansion mechanism is what drives length growth.

The other ideas describe growth that occurs at the surface (appositional growth), which adds layers and makes tissue thicker rather than longer. Growth involving periosteum relates to bone thickening, not internal cartilage lengthening. Calcification of cartilage is mineral deposition that stiffens tissue and does not constitute growth.