2. Movement: muscles attach by tendons and use bones as levers to move body
1. Skull – brain
2. Vertebrae – spinal cord
3. Rib cage – thoracic organs
4. Mineral storage
1. Calcium and phosphorus
2. Released as ions into blood as needed
5. Blood cell formation and energy storage
1. Bone marrow: red makes blood, yellow stores fat
Classification of bones by shape
2. Inner (deep) cellular osteogenic layer on the compact bone containing osteoprogenitor cells (stem cells that give rise to osteoblasts)
Osteoblasts: bone depositing cells
Also osteoclasts: bone destroying cells (from the white blood cell line)
b. Replacement of mesenchymal membrane with osseous tissue
c. Mesenchymal cells differentiate to osteoprogenitor cells, which then become osteoblasts
d. Osteoblasts create spongy bone, which then remodels into compact bone where necessary
Most bones formed this way
Mesenchyme creates Cartilage model, which gets replaced by bone
Replacement begins in middle (diaphysis) & follows in ends (epiphyses)
A)Cartilage model grows in length (interstitial growth) & in width (appositional growth)
Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calcifies.
B)Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone.
The perichondrium, which surrounded the cartilage model, now must be referred to as the periosteum.
D) Bone tissue continues to replace cartilage of the diaphysis, and & continues toward each epiphysis.
The medullary cavity begins to hollow out Blood vessels invade the epiphyses and osteoblasts form secondary centers of ossification.
Cartilage remains only at the ends (articular cartilage) & at metaphysis (epiphyseal plate)