MSK L5 Bone and Cartilage Flashcards
Matrix: Made up of
Inorganic/mineral
Organic
Matrix: Inorganic/mineral made up of
Hydroxyapatite
Matrix: Inorganic/mineral Function
Compression strength
→ without = bendy
Matrix:Organic made up of
Collagen and proteoglycans
→ without =brittle bones (osteogenesis impracta
Matrix: Organic part function
Flexible strength
Bones types:
- Cortical or compact – more dense
2. Cancellous (trabecular or spongy) – less dense – bars and plates interconnected
Matrix
Made up of many osteons
Osteon
Concentric layers of lamellae around central blood vessels.
Haversian canal
Contains blood vessels
Interstial lamellae
In between two osteon
Circumferential lamellae
Near matrix at surface
Canaliculi
Radiate from lacunae from mature bones and osteocytes into the haversian canal. Channels provide passageway through compact bone to provide nutrition to the cells.
Volkmann’s canal
Perforating blood vessels – allows them to join in outer membrane
Osteoblast
Forming bone (multinucleated)
Canaliculus
Radiate from lacunar of mature bone cell (osteocyte) into adjacent cavities with blood vessels to obtain nutrients.
2 types of bone development (ossification):
- Intramembranous → ossification of membrane to bone
2. Endochondral ossification→ calcification of cartilage model into bone
Bone Growth:
Apposition growth
Process (width)
Endochonral growth (length) process
Apposition growth
Process (width)
- OB in periosteum secrete matrix and become trapped as osteocytes
- Osteoclasts in crease diameter of medullary cavity
- Increases diameter of bones until skeletal maturity
Endochonral growth (length) process
- Requires interstitial growth from cartilage first
- Occurs at epiphyseal growth plates
- Stops when growth plates ossify
New bone laid down
Woven bone (random collagen)
Remodelled why
More orderly collagen fibres
Remodelling process
Osteoblasts lay down bone Osteoclasts resorbed (remove) bone → Lamellar bone (ordered formed)