Cartilage and Bone

Question 1

What are the skeletal tissues composed of?

Answer 1

bone and cartilage

Question 2

Which feature is common to all cartilages?

Answer 2

it has no blood vessels -avascular

Question 3

What are the types of cartilage?

Answer 3

hyaline cartilage, fibrocartilage, elastic cartilage

Question 4

What is the ground substance in cartilage made from predominantly?

Answer 4

the ground substance is chondroitin sulphate (GAG). functions to provides resistance to compression

Question 5

What are the cells of cartilage?

Answer 5

chondrocytes and chondroblasts

Question 6

What are the unique properties of cartilage ECM?

Answer 6

The ECM of cartilage unlike other tissues is firm, solid, and glassy.

Question 7

Describe hyaline cartilage

Answer 7

most common cartilage, abundant ground substance. smooth, gel like tissue that is perfect for lubricating joints, at the end of all long bones, and ribs. very tough and flexible and has significant compression strength.

Question 8

What is the perichondrium?

Answer 8

a dense connective tissue that surrounds hyaline cartilage and elastic cartilage externally

Question 9

Articular cartilage is a modification of which other type of cartilage?

Answer 9

hyaline

Question 10

How does cartilage receive nutrients?

Answer 10

Since there is no direct blood supply, chondrocytes receive nourishment via diffusion from the surrounding environment.

Question 11

Describe elastic cartilage

Answer 11

flexible, provides support and resistance to compression

Highly flexible, Outer ear/epiglottis
Histologically similar to hyaline cartilage
Elastin fibres concentrated around lacunae. Collagen fibres are also present

Question 12

What is lacunae in cartilage?

Answer 12

small chamber in the matrix occupied by one or more chondrocytes

Question 13

Describe fibrocartilage

Answer 13

Extremely durable and tough
Little ground substance
Dominated by irregular dense collagen fibres
Chondrocytes arranged in rows
Pads lie between spinal vertebrae, pubis, knee

Question 14

Which type of cartilage is dominated by dense bundles of collagen fibres?

Answer 14

fibrocartilage

Question 15

What does the ground substance of bone consist of?

Answer 15

Chondroitin sulphate
Hyaluronic acid

Question 16

What are the fibres in bone?

Answer 16

type 1 collagen

Question 17

What is the name of the organic unmineralised component of bone ECM?

Answer 17

osteoid

Question 18

What is the extracellular matrix in bone?

Answer 18

made up of organic matrix (30%) and hydroxyapatite (70%)
Before the ECM is calcified it is called osteoid

Question 19

What is the name of the mineralised component of bone matrix that confers hardness?

Answer 19

hydroxyapatite

Question 20

Apart from bone tissue what else are bones made from?

Answer 20

CT proper (periosteum)
Adipose tissue (fatty marrow)
Blood vessels
Nervous tissue
Articular cartilage

Question 20

What are the two conformations of bone?

Answer 20

Compact (cortical) bone
Spongy (trabecular) bone

Question 21

What are the cells in bone tissue and what is their function?

Answer 21

Osteogenic/osteoprogenitor cell
only bone cell capable of cell division. repair and maintain bone tissues
gives rise to osteoblasts

Osteoblast
Synthesises and secretes bone tissue (osteoid)
Gives rise to osteocytes

Osteocyte
Maintains mineralised bone tissue
once osteoblasts that differentiated

Osteoclast
Resorbs bone
Derived from monocyte/macrophage lineage

Question 22

How are osteocytes formed?

Answer 22

osteoblasts are surrounded by the growing bone matrix. once osteoblasts lay down the matrix that becomes mineralised, they become trapped in a lacunae. They become osteocytes to maintain material they previously laid down

Question 23

Bone is arranged in layers. What general name is give to these layers?

Answer 23

lamellae

Question 24

What is the periosteum?

Answer 24

The periosteum is a dense outer layer. It has two layers, an outer fibrous layer and an inner osteogenic layer. In the osteogenic layer there is osteogenic cells that give rise to osteoblasts

Question 25

What is the name of the functional unit of compact bone that is arranged in a series of concentric lamellae?

Answer 25

osteon

Question 26

What is in the middle of osteons?

Answer 26

central canals carry blood vessels, nerves and lymphatics

Question 27

What name is given to the tiny canals through which osteocytes maintain direct contact with their neighbours?

Answer 27

canaliculi

Question 28

What name is given to the layers of bone that lie between osteons and represent the remnants of old partially resorbed osteons?

Answer 28

interstitial lamellae

Question 29

What functional feature of compact bone is not evident in spongy/trabecular bone?

Answer 29

osteon

Question 30

How does spongy bone receive nutrients?

Answer 30

in spaces between which are red and yellow marrow, there are blood vessels and lymphatics present

Question 31

Trabeculae are lined externally by a cellular layer known as what?

Answer 31

endosteum

Question 32

What are factors that influence bone remodelling?

Answer 32

Bone remodelling can be influenced by growth, mechanical stress, hormonal and immunological

Question 33

What is healthy bone tissue?

Answer 33

when bone formation (osteoblastogenesis) is coupled with bone resorption (osteoclastogenesis)

Question 34

What happens in inflammation of bone tissue?

Answer 34

In inflammation, some diseases can disrupt the balance between bone formation and bone resorption leading to loss of bone and increase osteoclast diagenesis

Question 35

What happens in periodontitis?

Answer 35

Inflammation causes immune cells to migrate to the tissues. Other inflammatory molecules present in the tissues can cause monocytes to fuse and differentiate into osteoclasts so that the number of osteoclasts will outweigh the number of osteoblasts As a result bone remodelling has become uncoupled – increased osteoclastogenesis which causes destruction of alveolar bone and tooth loss

Question 36

What happens in oestoarthritis?

Answer 36

Cartilage is worn down causing movement to become difficult and painful

Question 37

What is rheumatoid arthritis?

Answer 37

an autoimmune disease where the body attacks it's own tissues

Question 38

Rickets is a condition that affects the bone structure of children. Which component of bone is most affected?

Answer 38

hydroxyapatite

Question 39

What are chondroblasts trapped in?

Answer 39

They become trapped in lacunae forming chondrocytes

Question 40

What type of cartilage is the epiglottis?

Answer 40

elastic cartilage

Question 41

What is the difference between articular and hyaline cartilage?

Answer 41

articular covers the articular surfaces of synovial joints, it is a specialised hyaline cartilage that lacks a perichondrium

Question 42

Where is fibrocartilage found?

Answer 42

in the invertebral discs of the spine and menisci of the knee

Question 43

Where is hyaline cartilage found?

Answer 43

found on the end of all bones and joints

Question 44

Where is elastic cartilage found?

Answer 44

external ear and epiglottis, parts of the laryngeal cartilages and in the walls of the Eustachian tubes.