Reticular Tissue

Osteoprogenitor cells

Fibrous Layer: outter most

Osteogenic Layer: inner layer, very cellular.

Sharpey's fibers: collagen fibers that penetrate bone matrix and bind periosteum to bone. Located within osteogenic layer.

Type I collagen,

GAGs, Glycoproteins, Proteoglycans(Chondroitin sulfate, keratan sulfate.)

Calcium, Phosphate, (bicarbonate,citrate,Mg, K, Na)

Hydroxyapatite crystals-along collagen fibers

Found in bone mineral.

-Insoluble salt that forms from Calcium and Phosphate.

-closely associated with collagen fibrils,

-results in hardness and resistance of bone

-rapid mobilization- along a concentration gradient

-physical tranfer of ions into interstitial fluid , then to blood.

• Acts on Osteoblasts which release cytokines that stimulate Osteoclasts.
• Osteoclasts increases activity and there is increased bone resorption.
• The bone breaks down and releases Ca

• Acts directly on Osteoclasts
• Inhibits activity
• Stimulates bone deposition by Osteoblasts.

• Mineralized matrix with few collagen fibers.
• Anchors Haversian systems/osteons to each other.

Outter: "Rings" of bone tissue immediatly beneath periostium

Inner: surrounding medullary cavity

Partial lamellae between osteons

Parts of old osteons

• Bone marrow cavity expands.
• Thickness of compact bone stays the same.

• Happens in the head
• Mesenchyme differntiates directly into osteoblasts to form bone.

Cartilage→bone at the Epiphyseal Plate.

Epiphyseal Plate responsible for growth in length of bones. Everywhere except head.

• First area in the bone to begin the ossification process.
• Near the diaphysis(mid-section) in long bones.

• Begins after primary
• Located in the Epiphyses(end) of long bone

• Region between primary and secondary ossification

• Form tubercles (near epiphyses)
• Where large muscle groups attach to some bones

• Chondroblasts deposit cartilage form Callus: cartilage model of bone.
• Primary bone replaces it.