1. Histology of Bone & Ossification Vocab

2. Osteogenic (osteoprogenitor) cells
-go through cell division, develop into osteoblasts; found in endosteum and inner portion of periosteum
-assist in fracture repair
Bone resorption
-destruction of bone matrix by osteoclasts

3. Compact bone tissue consistency -few spaces
Calcification
-Hardening of bone tissue as salts are deposited into the collagen framework
Compact bone tissue consistency
-few spaces
-dense matrix, supportive connective tissue
-Calcium phosphate around collagen fibers

4. Compact bone tissue structure
-osteons arranged in concentric rings, held together by lamellae

5. Perforating (Volkmann’s) canals
-horizontal canals; perpendicular to central canal
-carry blood vessels into bone and marrow
Central (Haversian) canal
-vertical canal, extending lengthwise through the bone
-bring nerves/blood vessels into bone

6. Concentric lamellae -plate-like membrane Lacunae
-wrapped around long bone; binds osteons together
Lacunae
-spaces between lamellae which contain osteocytes

7. Spongy bone tissue structure -does not contain osteons
Canaliculi
-Tiny channels projecting from lacunae; osteocyte’s fingerlike projections are held here
Spongy bone tissue structure
-does not contain osteons
-consists of trabeculae
-lots of spaces

8. Trabeculae -strands of bone that make up an irregular “meshwork”/”lattice work” with spaces

9. Ossification
-the process of replacing other tissues with bone
Intramembranous ossification (occurs in the dermis, Produces bones such as mandible and clavicle)
-Osteogenic cells become osteoblasts
-Osteoblasts secrete matrix
-Osteoblasts become osteocytes
-Salts/minerals added- bone hardens
-Trabeculae fuse together forming spongy bone
-Blood vessels grow in spaces
-Red bone marrow forms

10. Endochondral ossification (bone replaces cartilage; most bones formed this way)
-Chondrocytes in the center of hyaline cartilage enlarge, calcify, and die, leaving cavities in cartilage -Blood vessels grow around the edges of the cartilage and osteogenic cells begin to change to osteoblasts. Produces layer of superficial bone around shaft which becomes compact bone
- Blood vessels enter the cartilage. Spongy bone develops at the primary ossification center in the shaft where bone tissue replaces cartilage. A marrow cavity is created.
-Capillaries and osteoblasts enter the epiphyses creating secondary ossification centers
- Epiphyses fill with spongy bone (no cavity in this region of the bone). On the ends, hyaline cartilage that remains is articular cartilage.

11. Epiphyseal line -When the cartilage of the epiphyseal plate (which allows for diaphysis of bone to increase in length) is replaced by bone, the epiphyseal line appears.

12. Bone remodeling -ongoing process
-old bone tissue replaced by new bone tissue
-also removed worn/injured bone to be replaced with new bone
-osteoclasts/osteoblasts