Endochondral Ossification (CH.6) – Flashcards

Endochondral ossification begins with the formation of what?

As the cartilage enlarges, chondrocytes near the center of the shaft (diaphysis) increase in size

The matrix begins to calcify. The enlarged chondrocytes then die & disintegrate= leave cavities within the cartilage

Blood vessels grow around the edges of the cartilage & the cells of the perichondrium convert to osteoblasts

The shaft ( diaphysis) of the cartilage then becomes enclosed in a superficial layer of bone

-Blood vessels penetrate the cartilage and invade the central region. -The fibroblasts in the blood vessels differentiate into osteoblasts and begin to produce spongy bone at the PRIMARY OSSIFICATION center

From the primary ossification center bone formation then spreads along the shaft (diaphysis) toward both ends of the former cartilage model

Remodeling occurs as growth continues, creating the medullary cavity

-The osseous (bone) tissue of the shaft (diaphysis) becomes thicker and the cartilage near each epiphysis is replaced by shafts of bone. -Further growth involves increases in length and diameter

capillaries and osteoblasts migrate into the epiphyses --> creating secondary ossification centers

-the epiphyses soon becomes filled with spongy bone -the metaphysis= epiphysis plate

-On the shaft side of the metaphysis, osteoblasts continuously invade the cartilage and replace it with bone -New cartilage is produced at the same rate on the epiphyseal side

At puberty the rate of epiphyseal cartilage production slows and the rate of osteoblast activity grows. --> the epiphseal cartilage gets narrow until it disapears = epiphyseal closure and the former line gets called epiphyseal line