Structure of Bone and Cartilage

Question 1

What are the two types of bone tissue?

Answer 1

• compact
• cancellous (spongy)

Question 2

Describe compact bone tissue

Answer 2

homogenous (solid)
- similar to other parts

Question 3

Describe cancellous bone tissue

Answer 3

network of bone
- small needle-like pieces of bone
- many open spaces

Question 4

Define osteons

Answer 4

Basic functional units of mature compact bone

Question 5

Structure of osteons

Answer 5

Osteocytes arranged in
- concentric layers
- around a central canal
- which contains blood vessels

Question 6

Define lamellae

Answer 6

network of thin plates (similar to osteons)
- structure of cancellous bone tissue

Question 7

Structure of lamellae

Answer 7

Meshwork of supporting bundles of fibers
- called trabeculae

Question 8

Composition of bone matrix

Answer 8

• hydroxyapatite
• calcium salts
• collagen fibers
• cells

Question 9

Proportion of hydroxyapatite in bones

Answer 9

2/3 of bone weight

Question 10

Proportion of collagen fibers in bones

Answer 10

1/3 of bone weight

Question 11

What are the bone cells?

Answer 11

• osteogenic cells
• osteoblasts
• osteocytes
• osteoclasts

Question 12

Osteogenic cells

Answer 12

Produce osteoblasts
Structure:
- periosteum - outer surface of bone
- endosteum - inner surface of bones

Question 13

osteoblasts

Answer 13

Bone forming cells

Question 14

Osteocytes

Answer 14

Mature bone cells
- 90-95%
- deep within the bone matrix

Question 15

Osteoclasts

Answer 15

Bone-destroying cells (5%)
- remove old bone
- dissolve minerals

Question 16

What cells are involved in bone remodelling?

Answer 16

• osteoblasts (forming)
• osteoclasts (destroying)

Question 17

Cartilage

Answer 17

Type of connective tissue
- important for bone formation
- strong, flexible & fibrous

Question 18

Structure of cartilage

Answer 18

• matrix
• chondrocytes cells
• perichondrium (covering)

Question 19

Matrix (in cartilage)

Answer 19

Firm gel
- contains polysaccharide derivative, chondroitin sulfates

Question 20

Chondrocytes

Answer 20

Occupy small chambers known as lacunae

Question 21

Perichondrium

Answer 21

Two layers:
outer fibrous region – protection & attachment

inner cellular layer – growth

Question 22

What are the types of fibres in cartilage?

Answer 22

• hyaline
• elastic
• fibrocartilage

Question 23

Describe hyaline

Answer 23

Closely packed collagen fibres

Question 24

Where is hyaline found?

Answer 24

Between
- ribs-sternum
- joint cavities
- windpipe

Question 25

Describe elastic

Answer 25

• numerous elastic fibres
• resilient & flexible

Question 26

Where is elastic found?

Answer 26

• vertebral column ligaments
• ear

Question 27

Describe fibrocartilage

Answer 27

• densely interwoven collagen fibres
• restricts movement

Question 28

Where is fibrocartilage found?

Answer 28

Intervertebral discs

Question 29

What are the two growth mechanisms in cartilage?

Answer 29

• interstitial growth
• appositional growth

Question 30

What is interstitial growth?

Answer 30

• cell division
• enlarges from within

Question 31

What is appositional growth?

Answer 31

cells of inner layer of perichondrium undergo repeated cycles of division
- so new layers of cartilage are added to the surface

Question 32

How does appositional growth work? (2)

Answer 32

• undergo repeated cycles of division
• new layers of cartilage added to surface