Injury and healing*

Question 1

What bones form through intramembrane ossification?

Answer 1

Flat bones (skull, clavicle, mandible, scapula)

Question 2

What bones form through endochondral ossification?

Answer 2

Long bones, ribs, vertebrae

Question 3

What are the steps of intramembrane ossification?

Answer 3

Mesenchymal cells-> bone

Question 4

What are the steps of endochondral ossification?

Answer 4

Mesenchymal cells ->cartilage->bone

Question 5

Describe the process of intramembrane ossification.

Answer 5

1. Condensation of mesenchymal cells, which differentiate into osteoblasts which secrete matrix (osteoid)
2. Secreted osteoid traps osteoblasts which become osteocytes. A bunch of them together form an ossification centre
3. Multiple ossification centres form and fuse. Trabecular matrix and periosteum form.
4. Compact bone develops superficial to cancellous bone. crowded blood vessels bring in mesenchymal cells and form red marrow

Question 6

Describe the process of endochondral ossification.

Answer 6

1. Bone collar formation
2. Cavitation
3. Periosteal bud invasion
4. Diaphysis elongation
5. Epiphyseal ossification
   Cartilage cells start replicating and produce matrix, which they get stuck in and die, being replaced by bone cells
   3.

Question 7

What model are long bones developed from?

Answer 7

Hyaline cartilage model

Question 8

Which takes longer, intermembrane or endochondral ossification?

Answer 8

Endochondral

Question 9

What is a primary ossification centre called?

Answer 9

Diaphysis

Question 10

What is a secondary ossification centre called?

Answer 10

Epiphysis

Question 11

How is immature bond laid down?

Answer 11

In a woven manner (disorganised and weak)

Question 12

How is immature bone converted into mature bone?

Answer 12

Mineralisation

Question 13

What is the structure of mature bone?

Answer 13

Lamellar (layer) structure (strong)

Question 14

What are the two types of mature bone?

Answer 14

Cortical and cancellous

Question 15

What is the structure of cortical bone?

Answer 15

Compact (dense) and lamellar

Question 16

What is the structure of cancellous bone?

Answer 16

‘Spongy’ honeycomb structure

Question 16

Is cortical bone suitable for weight baring?

Answer 16

Yes

Question 16

Is cancellous bone suitable for weight baring?

Answer 16

No

Question 17

What are the structural units of compact bone?

Answer 17

Osteons

Question 18

Describe the gross structure of an osteon.

Answer 18

Concentric lamellae around a central Haversian canal

Question 19

What does a Haversian canal contain?

Answer 19

Blood vessels, nerves and lymphatics

Question 20

What are lacunae?

Answer 20

Small spaces containing osteocytes

Question 21

What are Volkmann’s canals?

Answer 21

Transverse perforating canals

Question 22

Long bone structure
What is the connective tissue covering called?

Answer 22

Periosteum

Question 23

Long bone structure
What is the compact bone called?

Answer 23

Outer cortex

Question 24

Long bone structure
Do long bones have cancellous bone?

Answer 24

Yes

Question 25

Long bone structure
What does the Medullary cavity contain?

Answer 25

Yellow bone marrow

Question 26

Long bone structure
What artery does the long bone have?

Answer 26

Nutrient artery

Question 27

Long bone structure
Where is articular cartilage located?

Answer 27

On surface of bone on a joint only

Question 28

Where are osteogenic cells found?

Answer 28

Bone marrow and deep layers of periosteum

Question 29

Where are osteoblasts found?

Answer 29

Growing portions of bone including periosteum and endosteum

Question 30

Where are osteoclasts found?

Answer 30

Bone surfaces and sites of injured, old or unneeded bone

Question 31

Where are osteocytes found?

Answer 31

Entrapped in matrix

Question 32

What is the result of interstitial bone growth?

Answer 32

Increase in length