Bone and Cartilage

Question 1

What are the 2 groups of connective tissues?

Answer 1

1. Connective tissue proper (loose or dense)

2. Skeletal connective tissues (bone and cartilage)

Question 2

What are the 3 types of cartilage?

Answer 2

1. Hyaline cartilage
2. Fibrocartilage
3. Elastic cartilage

Question 3

What is cartilage?

Answer 3

Flexible, avascular connective tissues that provide support and resistance to compression

Question 4

What is the long shaft of bone termed?

Answer 4

Diaphysis

Question 5

What type of bone marrow is in the diaphysis?

Answer 5

Yellow bone marrow

Question 6

What type of cartilage is at the end of long bones?

Answer 6

Articular/hyaline cartilage

Can’t regenerate because there is no perichondrium

Question 7

What tissues make up bone?

Answer 7

• Bone tissue
• Connective tissue proper
• Adipose tissue
• Blood vessels
• Nervous tissue
• Cartilage

Question 8

Where would you find compact (cortical) bone?

Answer 8

In the diaphysis of long bones

Question 9

Where would you find spongy (trabecular) bone?

Answer 9

In the epiphysis (ends) of long bones

Question 10

What is an osteoid?

Answer 10

Unmineralised organic component of the ECM of bone

Question 11

Which substances make up the ground substance of the ECM of bone?

Answer 11

Hyaluronic acid and chondroitin sulphate

Question 12

What does an osteoblast do?

Answer 12

Synthesises and secretes bone tissue

Question 13

What does an osteocyte do?

Answer 13

Maintains mineralised bone tissue

Question 14

What does an osteoclast do?

Answer 14

Resorbs bone

Derived from monocyte/macrophage lineage

Question 15

What do osteogenic/osteoprogenitor cells do?

Answer 15

Bone cell precursors

Give rise to osteoblasts

Question 16

What are the precursors for osteoblasts?

Answer 16

Osteogenic/osteoprogenitor cells (stem cells)

Question 17

When an osteoblast gets trapped in the lacunae, what is it called?

Answer 17

An osteocyte

Question 18

What is the periosteum?

Answer 18

Outermost layer of fibrous connective tissue covering bone

Question 19

What are osteons?

Answer 19

Circular units that make up compact bone

Made up of layers called concentric lamellae

Question 20

Describe the canals at the centre of each osteon

Answer 20

• Central canal that runs through the length of the bone - contains blood vessels, nerves, and lymphatic vessels
• There are also longitudinal canals that connect the central canals together (perforating Volkmann’s canals)

Question 21

Where are the lacunae located?

Answer 21

Between the lamellae (the layers that make up osteons)

Question 22

What is circumferential lamellae?

Answer 22

Covers the circumference of the concentric lamellae

Question 23

What type of lamella is between each osteon?

Answer 23

Interstitial lamellae

Question 24

What are lamellae?

Answer 24

Layers of bone tissue

• Concentric lamellae
• Circumferential lamellae
• Interstitial lamellae

Question 25

How are osteocytes formed?

Answer 25

When osteoblasts get trapped in the lacunae

Question 26

What is the name of the tiny canals linking osteocytes together?

Answer 26

Canaliculi | Osteocytes in the lacuna project to others

Question 27

Describe the structure of spongey (trabecular bone)

Answer 27

- Contains lamellar bone - No osteons - Space between the trabeculae occupied by red and yellow marrow, nerves, lymphatics - Linked externally by endosteum

Question 28

Describe bone formation in healthy bone tissue

Answer 28

Bone formation is coupled with bone resorption

Question 29

What are osteoclasts?

Answer 29

Large multinucleate cells of phagocytic lineage

Question 30

How often is our full skeleton 'turned over'?

Answer 30

Every 10 years

Question 31

Name some factors that influence bone remodelling

Answer 31

- Exercise -> increased bone formation to withstand stress - Growth -> increased bone formation - Hormonal factors (e.g. if calcium is needed -> increased bone resorption) - Immune factors - Mechanical factors (e.g. intense exercise)

Question 32

What is osteomalacia?

Answer 32

- Failure of the osteoid to mineralise adequately - Dietary deficiencies: lack of calcium and/or phosphate - Lack of vitamin D - Bones are weak and prone to fracture - Associated with dental abnormalities: enamel hypoplasia (thin enamel) and delayed tooth eruption

Question 33

What can cause osteomalacia?

Answer 33

Dietary deficiencies: lack of vitamin D, lack of calcium/phosphate

Question 34

What are the 2 types of arthritis?

Answer 34

Osteoarthritis and rheumatoid arthritis

Question 35

Describe osteoarthritis

Answer 35

- More common than rheumatoid arthritis - Degenerative disease - Can't repair cartilage - Bone grows to replace cartilage - grinding of bone

Question 36

Describe rheumatoid arthritis

Answer 36

- Auto-immune - Immune system destroys cartilage - Very painful

Question 37

Describe periodontitis

Answer 37

- Destructive inflammatory disease - Immune response to oral bacteria leads to destruction of host tissues - Uncoupling of bone remodelling - Increased osteoclastogenesis (bone resorption) - Destruction of alveolar bone and subsequent tooth loss