Final answer:
The process where chondrocytes divide leading to expansion of cartilage tissue is known as interstitial growth. This is a phase in endochondral ossification where hyaline cartilage is replaced by bone, carried out by osteoblasts for bone formation and growth.
Step-by-step explanation:
When chondrocytes in lacunae divide and form new matrix, it leads to an expansion of the cartilage tissue from within. This process is called interstitial growth. During endochondral ossification, a type of bone development, hyaline cartilage is replaced by bone tissue. Blood vessels invade the spaces left by dead chondrocytes, enlarging the cavities and carrying osteogenic cells, which become osteoblasts. These osteoblasts then build new bone matrix, leading to bone formation and growth. This process is crucial for the lengthening of long bones during development.