Bone structure and function Part 1

Question 1

5. Where does connective tissue originate from?

Answer 1

embryonic mesoderm

Question 2

6. How is connective tissue characterised?

Answer 2

Characterised by abundance of matrix with few cells when mature

Question 3

7. What is the extracellular matrix composed of

Answer 3

composed of:
- Collagen and elastin fibres
- Ground substance

Question 4

Name 5 types of connective tissue cells

Answer 4

Fibroblast
Chondrocyte
Osteoblast
Myofibroblast
Adipocyte

Question 5

9. What is the function of a fibroblast?

Answer 5

secretes collagen and elastin for the ECM of most tissues

Question 6

10. What is the function of a chondrocyte?

Answer 6

secretes collagen II for the ECM of cartilage

Question 7

11. What is the function of a osteoblast?

Answer 7

secretes collagen I for the ECM of bone

Question 8

13. What is the function of an adipocyte?

Answer 8

storage and metabolism of fat

Question 9

12. What is the function of a myofibroblast?

Answer 9

secrete ECM and have contractile function

Question 10

15. What does reduced tensile strength from collagen disorders cause?

Answer 10

causes:
- tissue laxity
- joint hyper mobility
- susceptibility to injury

Question 11

16. What is bone?

Answer 11

Specialised connective tissue

Question 12

17. What 2 things does the structural strength of bone provide for the body?

Answer 12

-mechanical support
-protection

Question 13

18. What is bone a reservoir for?

Answer 13

Reservoir for calcium and phosphate in the body

Question 14

19. What role does bone play in regards to calcium?

Answer 14

role in calcium homeostasis

Question 15

22. What is the outside lining of a bone known as?

Answer 15

Periosteum

Question 16

23. Give 3 features of the periosteum

Answer 16

• Fibrous CT layer, limiting bone growth
• Carries blood supply and osteoprogenitor cells
• Not present at the joint ends of long bones

Question 17

24. What is the inner lining of a bone known as?

Answer 17

Endosteum

Question 18

25. Give a feature of the endosteum

Answer 18

Lines the interior of bones

Question 19

27. Where is bone marrow found in a bone?

Answer 19

medullary cavity

Question 20

29. What is compact bone arranged into?

Answer 20

osteons

Question 21

30. What is the dense outer shell of bone called?

Answer 21

compact bone

Question 22

31. What is compact bone parallel to?

Answer 22

parallel to the long axis

Question 23

32. What is 2 things is spongy bone also known as?

Answer 23

Trabecula bone
inner cancellous bone

Question 24

33. What is inner cancellous bone arranged into?

Answer 24

interconnecting trabeculae with spaces for bone marrow

Question 25

34. What are the spaces in trabeculae bone for?

Answer 25

spaces for bone marrow

Question 26

37. Give 3 features of woven bone

Answer 26

Immature Haphazard fibre arrangement Mechanically weak

Question 27

38. What is woven bone remodelled into after foetal development/fracture repair?

Answer 27

lamellar bone

Question 28

39. Give 3 features of lamellar bone

Answer 28

. regular parallel collagen arrangement . strong . all adult bone is lamellar bone

Question 29

40. What percentage of the bone matrix is organic?

Answer 29

25% organic

Question 30

41. What percentage of the bone matrix is inorganic?

Answer 30

66% inorganic

Question 31

44. What is the organic portion of bone called?

Answer 31

osteoid

Question 32

47. What are the 2 non-collagenous proteins in the organic bone matrix that we need to know about?

Answer 32

osteocalcin and osteonectin

Question 33

48. What is the function of osteocalcin

Answer 33

binds calcium together, increasing its local concentration

Question 34

49. What is the function of osteonectin?

Answer 34

binds calcium to collagen

Question 35

50. What is the name of the inorganic component of the bone matrix?

Answer 35

calcium salt-hydroxyapatite

Question 36

51. Give 3 features of the inorganic component of the bone matrix

Answer 36

66% of dry weight of bone Calcium phosphate with some carbonate and fluoride Deposited in collagen hole zones