Only $35.99/year

Chapter 6 - Bone

Terms in this set (27)

Mesenchyme tissue becomes cartilage then forms bone. This is the most common method of bone formation in the body. Six steps:

1) Development of cartilage model - chemical messages from the body cause mesenchyme cells to differentiate into chondroblasts (cartilage cells). Chondroblasts secrete cartilage (ecm) and make a cartilage model of the bone. This cartilage is hyaline.
2) Growth of cartilage model - chondrocytes cause cell division and the cartilage model to grow.
3) Development of primary ossification center - the first area where ossification will occur. In the mid-region of the cartilage model the nutrient artery enters. Chondrocytes differentiate to osteogenic cells. Osteoblasts form and develop the bony extracellular matrix. Ossification will continue from the center towards each epiphysis.
4) Development of medullary cavity - as ossification grows towards the epiphysis osteoclasts break down the spongy bone forming the medullary cavity. The compact bone of the diaphysis remains.
5) Development of secondary ossification center - the epiphyseal artery enters the epiphysis starting a secondary ossification center, same cycle of cell differentiation occurs in step 3.
6) Formation of articular cartilage of epiphyseal plate - the ossification centers grows and leaves the outer surface with cartilage. The hyaline cartilage that remains becomes the articular cartilage. The hyaline cartilage that remains between the diaphysis and epiphysis is known as the epiphyseal growth plate. The epiphyseal growth plate is where new bone grows during adolescence.