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Flashcards in Bone Deck (27):
1

What are the four main functions of bone?

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

2

What is the difference between cortical and trabecular bone?

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

3

What is the difference between the periosteum and the endosteum?

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

4

What are Haversion systems?

Compact bone organised into circular structures

5

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

Haversion canals lead up the centre of Haversion systems.
Volkmann's canals lead horizontally through Haversion systems.

6

What is the other name for Haversion systems?

Osteons

7

What are the 6 types of bone?

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

8

Where do sesamoid bones occur?

Where there is a risk of friction

9

What are the two types of bone formation?

Intramembranous and Endochondral

10

Describe endochondral bone formation.

Hyaline cartilage model is replaced by bone

11

Describe intramembranous bone formation.

(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.

12

What bones are formed by intramembranous ossification?

Flat bones of skull, face, jaw and clavicle

13

What three cells are present in bone?

Osteoblasts, Osteoclasts, Osteocytes

14

What are the constituents of bone extracellular matrix?

Hydroxyapatite crystals
Type 1 Collagen
Water

15

From what cells are osteoblasts formed?

Osteoprogenitor cells

16

What is the function of osteoblasts?

Produce bone matrix and initiate calcification

17

From what cells are osteoclasts formed?

Monocytes/ macrophages

18

What is the function of osteoclasts?

Reabsorb bone matrix

19

How are osteocytes formed?

From maturation of osteoblasts once surrounded by matrix.

20

What is though to be the function of osteocytes?

Maintenance of bone matrix
Sense mechanical forces

21

What is the role of canaliculi?

Connect lacunae to allow cell to cell communication

22

From what compound are hydroxyapatite crystals formed?

Calcium phosphate

23

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

Makes bones stiff for support and gives high tensile strength.

24

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

Allows flexibility of bone to make it less brittle.

25

What processes characterise osteoporosis?

Greater reabsorption than formation

26

What processes characterise Paget's disease?

Increased reabsorption and Formation

27

What process characterises osteopetrosis?

Decreased reabsorption