Bone and Cartilage

Question 1

What are the two types of macroscopic bone?

Answer 1

Cortical: Dense. Found at edges of bones. Outer plate.

Cancellous: Spongy

Question 2

What is the cortical bone lining tooth sockets penetrated by?

Answer 2

Sharpeys fibres.

Question 3

In the organic mass of bone, what are glycoproteins important for?

Answer 3

Bone regeneration

Question 4

What fibres are found in the extracellular matrix of bone?

Answer 4

Collages

Elastin

Question 5

Name the 2 types of microscopic bone.

Answer 5

Woven: 
Rapid laying
Irregular
Fracture repair
Lots of osteocytes present.

Lamellar:
Slow laying
Parallel collagen fibres
Less osteocytes than woven bone.

Question 6

Comment on the arrangemnt of compact bone structure.

Answer 6

Concentric lamellae formed in longitudinal columns.

Filled with Haversian systems/canals and volkmann’s canals (LATERAL)

Question 7

What is the function of Volkmann’s canals?

Answer 7

Links Haversian canals

Question 8

What is an osteon?

Answer 8

Lamellae surrounding a haversian canal.

Question 9

What is a Haversian system?

Answer 9

Functionl unit of compact bone.

Question 10

What is a Haversian canal?

Answer 10

A canal containing blood vessels, nerves and lymphatics.

Question 11

List the characteristics of cancellous bone.

Answer 11

No obvious Haversian systems.
Bone is thin = nutrients can diffuse.
Bone marrow present in the spaces between trabeculae.

Question 12

What is osteoblast?

Answer 12

Synthesise and secrete collagen fibres = matrix.

Question 13

Where are osteoblasts found?

Answer 13

Lie on the surface of bone.

Question 14

Where are osteoblasts derived from?

Answer 14

mesenchymal stem cells.

Question 15

What are osteocytes?

Answer 15

An osteoblast that gets trapped in mineralised bone.

Question 16

Where are osteocytes found?

Answer 16

Lie within the lacunae (spaces)

Question 17

What are osteocytes able to do via their cytoplasmic processes that run in canaliculi?

Answer 17

Communicate with other osteocytes.

Can also communicate with osteoblasts.

Question 18

What are osteoclasts?

Answer 18

Cells that resorb bone via acid phosphatases.

Question 19

Where are osteoclasts derived from?

Answer 19

Haemopoietic stem cells

Question 20

Define bone remodelling.

Answer 20

Removal and replacement of bone tissue without change in the overall shape.

Question 21

What cell controls bone remodelling?

Answer 21

Osteoblasts

Question 22

What is bone remodelling regulated by?

Answer 22

Hormones: Parathyroid and calcitonin.

Paracrines: Cytokines.

Question 23

What is the advantage of bone remodellin?

Answer 23

Maintains a level of calcium within the body.

Question 24

In bone remodelling, what is a reversal line?

Answer 24

Scalloped edge that shows where bone resorption changes to bone deposition.

Question 25

When does tooth movement occur?

Answer 25

Eruption Post eruptive i.e. drifting Ortho treatment

Question 26

Cartilage is...?

Answer 26

Connective tissue

Question 27

Name the 3 types of cartilage

Answer 27

Hyaline cartilage Fibrocartilage Elastic cartilage

Question 28

What cells produce cartilage?

Answer 28

Chondroblasts.

Question 29

What are chondrocytes?

Answer 29

Chondroblasts after they become trapped in the matrix.

Question 30

Name the 2 types of bone growth.

Answer 30

Endochondral Intramembranous

Question 31

What is endochondral ossification?

Answer 31

Growth in long bones that includes cartilage being replaced with bone.

Question 32

What is intramembranous ossification?

Answer 32

Growth of flat bones, no cartilage (precursor)

Question 33

Where does cartilage proliferation occur in endochondral ossification?

Answer 33

At the epiphyses plates.

Question 34

What is achondroplasia?

Answer 34

Genetic defect in cartilage growth. ENDROCHONDRAL bone impaired. (Sphenoid bone at base of skull is unable to grow, yet Intramembranous bones creating the cranium can grow.)