Essentials of Anatomy and Physiology

B Epiphyseal disc

Chondrocytes producing cartilage

Bone

Cartilage

Epiphyseal

disc

Cartilaginous

model

Medullary cavity

containing

marrow

Bone collar

and calcifying

cartilage in

ossification center

Secondary

ossification

center

Compact bone

Compact bone

Spongy bone

Articular cartilage

Medullary cavity and development

A of secondary ossification centers

Osteoblasts producing bone

Figure 6–3. The ossification process in a long bone. (A) Progression of ossification from

the cartilage model of the embryo to the bone of a young adult. (B) Microscopic view of

an epiphyseal disc showing cartilage production and bone replacement.

QUESTION:The epiphyseal discs of the bone on the far right are closed. What does that

mean?

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