Lecture 14

Question 1

What are the three types of cartilage?

Answer 1

Hyaline- type 2 collagen

Ellastic

Fibrocartilage- type 1 collagen

Question 2

What is common between all types of cartilage?

Answer 2

All have proteoglycan and hyaluronic acid containing matrix and chondrocytes

Question 3

Can cartilage repair itself?

Answer 3

No, you get scar tissue instead of it

Question 4

Difference between endochondral and intramembranous ossification?

Answer 4

Endochondral occurs from existing fetal cartilage.

Question 5

What way are chondrocytes found?

Answer 5

In groups called isogenous groups that separate as they lay down matrix. Found in depressions called lacunae.

Question 6

Where is cartilage left in long bones?

Answer 6

At the epiphyseal growth plate and articular surface (at the end of bone)

Question 7

Why is hyaluronic acid important for the matrix of cartilage?

Answer 7

Attracts water which helps resist compression

Question 8

What is the role of proteoglycans?

Answer 8

Bind with hyaluronic acid to form hyaluronate proteoglycan aggregates which forms a stiff gel like substance.

Question 9

Where would you find hyaline cartilage?

Answer 9

The nose, trachea and forms the articular cartilage of joints.

Question 10

What covers hyaline cartilage?

Answer 10

Perichondrium which is made of dense connective tissue

Question 11

What are the two types of growth in cartilage?

Answer 11

Appositional from the periphery and interstitial from the centre

Question 12

What is the difference between a chondrocyte and chondroblast?

Answer 12

A chondroblast is active or immature and then becomes a chondrocyte when it is inactive or mature.

Question 13

What is the role of cartilage in rheumatoid arthritis?

Answer 13

Cartilage is broken down and cannot repair itself so fibroblasts from surrounding connective tissue lay down scar tissue which calcifies with age and flexibility is lost.

Question 14

Where are the three places in the body where elastic cartilage is found?

Answer 14

Pinna of ear

Eustachian tube

Epiglottis

Question 15

What cells are in elastic cartilage?

Answer 15

Just chondrocytes

Question 16

What cells are in fibrocartilage?

Answer 16

Chondrocytes and fibroblasts. No perichondrium

Question 17

What is fibrocartilage made of?

Answer 17

Dense connective tissue and hyaline cartilage combination. Dense connective tissue helps resist shearing forces.

Question 18

Where would you find fibrocartilage?

Answer 18

The meniscus (pad like cartilage in knee joint) and intervertebral disks.

Question 19

What are two common injuries seen by GP’ and orthopaedic surgeons?

Answer 19

Intervertebral disk (prolapse) and knee meniscus

Question 20

What are the three main sections of long bone called?

Answer 20

Epiphysis, diaphysis and metaphysics in between where the growth plate is located

Question 21

Describe the process of endochondral ossification

Answer 21

Begins with a hyaline cartilage model

Collar of periosteal bone appears in shaft.

Centre of cartilage than ossified and a nutrient artery enters supplying the new primary ossification centre with nutrients for the osteogenic cells.

Medulla becomes cancellous bone . Two epiphyseal growth plates and secondary ossification centres form.

The epiphyses ossify while the two growth plates continue to move apart which lengthens the bone

Eventually the growth plates are replaced by bone and and only hyaline articular cartilage persists.

Question 22

How is the girth of a long bone extended?

Answer 22

Intramembranous ossification

Question 23

What is the function of organic and inorganic components of bone?

Answer 23

Inorganic resist bending and compression. Organic resists pulling and tension.

Question 24

How are bony spicules grown?

Answer 24

By osteoblasts which then become trapped and become osteocytes

Question 25

What are the cells of bone?

Answer 25

Osteprogenitor cell which becomes an osteoblasts which becomes an osteocytes when trapped and mature and no longer lays down new tissue but rather maintains existing tissue.

Question 26

What is compact bone structure?

Answer 26

Circular units called osteons made up of concentric lamellae with osteocytes between them that sit in lacunae and a haversian canal in the centre. Volkmans canals link Haversian canals. The osteoclasts are on the outside of compact bone at the periosteum.

Question 27

What’s the main difference between osteoarthritis and rheumatoid arthritis?

Answer 27

Osteoarthritis involves breakdown of just cartilage whereas rheumatoid involves cartilage and bone. Pain in osteoarthritis caused by growth of bony spurs which osteoclasts cannot break down

Question 28

What causes pain in rheumatoid arthritis?

Answer 28

Osteoclasts degrade bone and macrophages recruited to digest who then cause immune response and inflammation. Fibroblasts lay down scar tissue