Bone cells, cartilage and function

Question 1

What are the functions of bone in the body?

Answer 1

Support and muscle attachment. Houses haematopoiesis (formation of blood cells from stem cells). It is needed for protection and as a reservoir for calcium and phosphate.

Question 2

What are the percentages of what makes up bone?

Answer 2

25% matrix (90% type 1 collagen, 5% protein, 5% water)

75% minerals (inorganic hydroxyapatite which is calcium-phosphate material)

Question 3

What happens when you add acid or bleach to bone?

Answer 3

Acid dissolves the minerals and bleach dissolves the minerals

Question 4

What are the 3 sections of a long bone called and where can you find the growth plate?

Answer 4

Epiphysis (end)
Metaphysis
Diaphysis (centre)

Growth plate in the metaphysis

Question 5

Name and describe the cells found in bone

Answer 5

Osteoblasts
- bone forming cells
- cuboidal
- sit on bone surface
Osteoid 
- matrix not yet mineralised 
Osteocytes
- formed from osteoblasts
- embedded in lacunae 
- connected via canaliculi
Lining Cells
- lie on surface
Osteoprogenitor cells
- osteoblast precursors
- found in periosteum
- sit above osteoblasts as they are not yet osteoblasts
Osteoclasts
- only cells in body which degrade bone 
- sit in holes called Howship/s lacunae 
- multinucleated

Question 6

Where is hyaline cartilage, fibrocartilage and elastic cartilage found?

Answer 6

Hyaline = trachea, articular joints, ribs
Fibro = intervertebral disc and tendon
Elastic = ear, larynx

Question 7

What does type 1 and type 2 collagen make up?

Answer 7

1 = skin, bone, tendons, dentine
2 = cartilage

Question 8

What is a proteoglycan?

Answer 8

A glycoprotein which consists of a protein attached to a GAG.

Question 9

List the differences between bone and cartilage

Answer 9

B = rigid, C = deformable 
B = impermeable, C = permeable 
B = 25% matrix, 75% mineral, C = 25% matrix, 75% water 
B = appositional, C = appositional and interstitial 
B = vascularised, C = not vascularised

Question 10

What cells come from mesenchymal stem cells? What cells come from heamatopoietic stem cells?

Answer 10

osteoblasts, osteocytes, lining cells, osteoprogenitor cells, chondrocytes

osteoclasts, monocytes/macrophages

Question 11

What is the difference between woven and lamellar bone?

Answer 11

Woven = immature bone, fracture healing, irregular collagen fibres, high cellular content, less calcified 
Lamellar = all mature bone, low cellular content, heavily calcified

Question 12

How are cortical and trabecular bone arranged?

Where are Haversian systems found?

Answer 12

Cortical - rings
Trabecular - sheets

Cortical bone

Question 13

What is the function of a Haversian system/osteon?

Answer 13

A system of lamellae containing blood vessels and nerves. Communication between them occurs via osteocytes.

Question 14

What is the function of a Haversian canal?

Answer 14

Nutrient canals, allowing communication between osteons.

Question 15

How many lamellae is an osteon limited to and why/

Answer 15

6 lamellae because the nutrients have to pass the whole way via diffusion