Cartilage and bone

Question 1

What are the features of cartilage?

Answer 1

Semi-rigid and strong but slightly flexible
Withstands compression forces such as weight-bearing but can also bent
It has a major role during development and growth of long bones
Avascular

Question 2

What is meant by avscular?

Answer 2

little or no blood vessels

Question 3

What is the significance of blood vessels being avascular?

Answer 3

The cells in the cartilage have to get their oxygen and nutrients by long range diffusion

Question 4

What are the cells of cartilage?

Answer 4

Chondrocytes

Question 5

What do chondrocytes originate as?

Answer 5

Develop from chondroblasts

Question 6

What is the role of chondrocytes?

Answer 6

Produce the extracellular matirx

Question 7

Where are chondrocytes located

Answer 7

Within matrix enclosed compartments (lacunae)

Question 8

What are the three types of cartilage?

Answer 8

Hyaline
Elastic
Fibrocartliage

Question 9

Where is hyaline cartilage found?

Answer 9

Articular surfaces of bones
Trachea and bronchus
Costal cartilages
Nasal cavity & nose

Question 10

Where is elastic cartilage found?

Answer 10

Pinna of external ear

Epiglottis

Question 11

Where is fibrocartilage found?

Answer 11

Tendon insertions
Pubic symphysis
Intervertebral discs
Articular menisici

Question 12

What does the matrix of hyaline cartilage comprise of?

Answer 12

Collagen type II fibres embedded in a firm hydrated gel of proteoglycans and structural glycoproteins

Question 13

What does elastic cartilage have in abundance?

Answer 13

elastic fibres

Question 14

What is fibrocarttilage?

Answer 14

Intermediate between dense irregular CT and hyaline cartilage

Question 15

Describe the arrangements of chondrocytes

Answer 15

Arranged in straight rows separated by collagen type 1 fibres

Question 16

What is the role of fibrocartilage?

Answer 16

Combines tensile strength with shock absorption and resists compression

Question 17

What is the role of bone?

Answer 17

Protects internal organs 
Stores and releases fat
Produces blood cells 
Stores and releases minerals 
Facilitates Movement
Supports the body

Question 18

What does the bone matrix consist of?

Answer 18

Collagen type I - 95% of organic matrix

Question 19

How does the matrix harden?

Answer 19

The binding of calcium phosphate in the form of hydroxyapatite crystals which surround fibres

Question 20

What are the three types of bone cells?

Answer 20

Osteoblasts
Osteoclasts
Osteocytes

Question 21

What is the role of osteoblasts?

Answer 21

Form bone matrix and respnsible for the production of the ECM

Question 22

What is the role of osteocytes?

Answer 22

Maintain bone matrix

Principle bone cell of the adult skeleton

Question 23

What is the role of osteoclasts?

Answer 23

Resorb bone caused by releasing enzymes

Question 24

What is an osteoid?

Answer 24

The unmineralised component of bone

Question 25

Where are osteoblasts located?

Answer 25

Exclusively located at the surfaces of bone tissue

Question 26

How do osteoblasts become osteocytes?

Answer 26

Gradually surrounded by matrix and become trapped in matrix

Question 27

Where do osteoblasts originate?

Answer 27

Develop form an osteoprogenitor cell

Question 28

Where are osteocytes found?

Answer 28

lacunae

Question 29

How do lucanae connect to each other?

Answer 29

Through small channels called canaliculi

Question 30

What does the canaliculi allow?

Answer 30

Allows the flow of nutrients and oxygen through the matrix

Question 31

Where do osteoclasts derive from?

Answer 31

The monocyte phagocyte line

Question 32

Describe the shape of osteoclasts

Answer 32

Very large, motile cells multinucleate highly folded forming a ruffled border

Question 33

Where are the osteoclasts located?

Answer 33

Sit on bone surface often in depression called howships lacunae

Question 34

What are the two types of bones?

Answer 34

Compact (cotical) | spongy (trabecular/cancellous)

Question 35

What does compact bone comprise of?

Answer 35

Collagen fibres arranged in concentric lamellae around and canal containing blood vessels and nerves (osteon/haversion system)

Question 36

What does spongy bone comprise of?

Answer 36

Bone organised into plates of bone called trabeculae/spicules Lamellae in trabeculae are arranged concentrically- however there is no central canal Osteocytes- that sit in lacunae between lamellae Trabeculae sit adjacent to red marrow spaces

Question 37

What is periosteum?

Answer 37

Dense irregular CT cover outer surface of bone | Contains osteoprogenitor cells

Question 38

How does periosteum bind ot bone?

Answer 38

Through bundles of collagen fibres penetrating the bone matrix

Question 39

What is endosteum?

Answer 39

single layer of osteoprogenitor cells and a very small amount of CT

Question 40

What is the main function of periosteum or endosteum?

Answer 40

Provide nutrients to bone tissue and provision of new bone cells