Bone

Question 1

What are the four main functions of bone?

Answer 1

1. Weight bearing/ support
2. Protection (e.g. skull protecting brain)
3. Mineral store
4. Blood formation

Question 2

What is the difference between cortical and trabecular bone?

Answer 2

Cortical (Hard) bone is more compact than trabecular (spongy) bone

Question 3

What is the difference between the periosteum and the endosteum?

Answer 3

The periosteum is the outer membrane and the endosteum is the inner membrane.

Question 4

What are Haversion systems?

Answer 4

Compact bone organised into circular structures

Question 5

What is the difference between Haversion canals and Volkmann’s canals?

Answer 5

Haversion canals lead up the centre of Haversion systems.

Volkmann’s canals lead horizontally through Haversion systems.

Question 6

What is the other name for Haversion systems?

Answer 6

Osteons

Question 7

What are the 6 types of bone?

Answer 7

1. Sutural bone
2. Flat bone
3. Long bone
4. Short bone
5. Irregular bone
6. Sesamoid bone

Question 8

Where do sesamoid bones occur?

Answer 8

Where there is a risk of friction

Question 9

What are the two types of bone formation?

Answer 9

Intramembranous and Endochondral

Question 10

Describe endochondral bone formation.

Answer 10

Hyaline cartilage model is replaced by bone

Question 11

Describe intramembranous bone formation.

Answer 11

(Membrane becomes replaced by bone)
Mesenchymal cells develop into osteoprogenitor cells
Osteoprogenitor cells mature into osteoblasts
Osteoblasts deposit bone
Residual mesenchymal cells develop into blood vesseks and bone marrow.

Question 12

What bones are formed by intramembranous ossification?

Answer 12

Flat bones of skull, face, jaw and clavicle

Question 13

What three cells are present in bone?

Answer 13

Osteoblasts, Osteoclasts, Osteocytes

Question 14

What are the constituents of bone extracellular matrix?

Answer 14

Hydroxyapatite crystals
Type 1 Collagen
Water

Question 15

From what cells are osteoblasts formed?

Answer 15

Osteoprogenitor cells

Question 16

What is the function of osteoblasts?

Answer 16

Produce bone matrix and initiate calcification

Question 17

From what cells are osteoclasts formed?

Answer 17

Monocytes/ macrophages

Question 18

What is the function of osteoclasts?

Answer 18

Reabsorb bone matrix

Question 19

How are osteocytes formed?

Answer 19

From maturation of osteoblasts once surrounded by matrix.

Question 20

What is though to be the function of osteocytes?

Answer 20

Maintenance of bone matrix

Sense mechanical forces

Question 21

What is the role of canaliculi?

Answer 21

Connect lacunae to allow cell to cell communication

Question 22

From what compound are hydroxyapatite crystals formed?

Answer 22

Calcium phosphate

Question 23

What is the function of hydroxyapatite crystals in the extracellular matrix?

Answer 23

Makes bones stiff for support and gives high tensile strength.

Question 24

What is the role of the collagen found in the extracellular matrix of bone?

Answer 24

Allows flexibility of bone to make it less brittle.

Question 25

What processes characterise osteoporosis?

Answer 25

Greater reabsorption than formation

Question 26

What processes characterise Paget’s disease?

Answer 26

Increased reabsorption and Formation

Question 27

What process characterises osteopetrosis?

Answer 27

Decreased reabsorption