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Flashcards in Bone Deck (27):
1

What are the three main functions of bone?

- Weight bearing/support
- Mineral store
- Hematopoiesis

2

What is the name of the hard bone on the outside?

Cortical bone

3

How is cortical bone organised?

- Osteons
- Haversian systems

4

What are the two canals that exist in haversian systems?

- Central Haversian canal
- Horizontal volkmanns canal

5

What surrounds a haversian canal?

- Osteocytes
- Concentric rings of bone matrix

6

What is spongy bone called

Trabecular

7

What is the structure of trabecular bone?

- Network of lamellated trabeculae

8

Which direction do the trabeculae run?

In the same direction as the main mechanical force of the bone

9

What is the name of the cavity inside the bone

Medullary cavity

10

What are the 6 types of bone? (FISSSL)

- Flat
- Irregular
- Sesamoid
- Sutural
- Short
- Long

11

What are the two types of ossification?

- Endochronal
- Intramembranous

12

Which bones grow using endochronal ossification?

- Long bones

13

What bones grow intramembranously?

- Flat bones

14

Name the bones in the body that ossify intramembranously

- Flat bones in the skull
- Mandible
- Maxilla
- Clavicles

15

Describe the stages of endochondral ossification

- Cartilage model forms initially
- Blood vessels invade cartilage model
- Cartilage replaced with bone
- Cartilage remains at epiphyseal growth plate for growth

16

Describe the stages of intramembranous ossification

- No cartilaginous stage
- Mesenchymal cells mature into osteoblasts and start depositing bone
- Other mesenchymal cells become blood vessels

17

What three cells are involved in bone

- Osteoblasts
- Osteoclasts
- Osteocytes

18

What % of the extracellular matrix is hydroxyapatite?

45%

19

What does hydroxyapatite do to bones?

Makes them stiff and able to support structures

20

What % of the extracellular matrix is collagen?

35%

21

What does collagen give the bone?

Flexibility

22

What cells mediate the bones ability to remodel?

- Osteoclasts degrade old bone
- Osteoblasts build up new bone

23

In what membranes are osteoblasts created?

- Periosteum
- Endosteum

24

What is the osteoid?

Unmineralised matrix

25

What bone disease can result of greater reabsorption by osteoclasts than laying down of new bone by osteoblasts?

Osteoporosis

26

What disease results in a decrease of bone reabsorption?

Osteopetrosis

27

Why does bone mass reduce after menopause?

- Oestrogen normall inhibits bone breakdown
- Less oestrogen produced