Bone

Question 1

4 Key points about bone

Answer 1

structural support
store calcium
dynamic vascular tissue
ECM has calcium phosphate crystals + Type I collagen

Question 2

3 sections of a bone?

Answer 2

epiphysis
— epiphyseal line —
metaphysis
diaphysis

Question 3

2 layers of bone?

Answer 3

periosteum and endosteum

Question 4

2 types of bone?

Answer 4

compact bone
trabecular/cancellous bone = no canals with blood

Question 5

Bone matrix composition?

Answer 5

1/3 water
1/3 hydroxyapatite
1/3 organic (type I collagen + proteoglycans)

Question 6

4 cell types in bone?

Answer 6

Osteoprogenitor (mesenchymal stem cell)
Osteoblasts
Osteocytes
Osteoclasts

Question 7

Periosteum function and composition?

Answer 7

cover outer surface of bone
- fibrous = dIRCT
- osteogenic

Question 8

Endosteum function and composition?

Answer 8

cover inner surface of bone
- single cell layer

Question 9

Osteoprogenitors location, appearance and function?

Answer 9

• periosteum + endosteum
• flattened
• produce osteoblasts

Question 10

Osteoblasts location and function?

Answer 10

• line bone
• secrete osteoid (pre-bone matrix) AND release matrix vesicles of hydroxyapatite

Question 11

Osteocytes appearance and function?

Answer 11

• enclosed in osteoid and residue in a lacuna
• connected by canaliculi (metabolic process signals)
• mechanosensory

Question 12

Osteoclast formation, appearance and function?

Answer 12

• fusion of blood monocytes
• large, multi nucleated, eosinophilic, RESORPTION BAY
• resorbs bone

Question 13

Osteoclast activity 3 steps?

Answer 13

1) create seal with adhesion molecules
2) drop pH - decalcify matrix
3) lysosome fuse with PM, release into Resorption Bay

Question 14

Compact Bone characteristics?

Answer 14

• Osteons with Concentric lamella with osteocytes
• Haversian canal in middle (carries blood and nerves)
• Interstitial lamella and Volkmann’s Canal in between

Question 15

Bone remodelling?

Answer 15

• osteoclasts resorbs bone
• osteoblasts make new bone