-cuboidal with basal infoldings

-spherical polar (apical nucleus)

-basophilic cytoplasm

-found on surfaces of bones

-produces osteoid

-cytoplasmic extensions

-spherical nucleus

-less basophilic, slighly acidophilic

-lives in lacunae

-talks with other osteocyte through canaliculi bone

-large

-multinucleate cells acidophilic cytoplasm

-irregular "ruffled" border

-degrative enzymes digest bone

-found on surfaces in Howship's lacunae

-cancellous bone

-irregular arrangement of spicules (points) and trabeculae (bars)

-nutrients from marrow cavity

-regular arrangement in circular layers (lamellae)

-Haversian canal

Volkman vessels run perpendicular to axis of bone

• immature bone
• rapidly formed
• irregular collagen fibers
• remodeled to mature bone

• happens in CT
• foundation for growth of flat bones and bone from Peri & endostea
• mesenchyme arrange in flat sheets
• vascularization of membrane occurs bringing in molecules & stem cells
• mesenchyme separates to osteoblasts (osteoprogenitor cells from blood)
• osteoblasts make changes in the EC matris, secrete osteoid, calcification then occurs, lacunae formed and product is woven bone

Endochondral Ossification

• destruction of cartilage & production of bone
• perichondrium changes (vascularization) to periosteum
• bony collar
• woven bone is formed and osteoblasts erode internally to form marrow cavity
• "growth plates"

• hemorrage occurs and clot is formed
• fibroclasts and capillaries and stem cells migrate to area form granulation tissue= "procallus"
• procallus is transformed to cartilage "callus"
• osteoblasts-transform cart. to bone
• osteoclasts-resorb and remodel excess