Cartilage and Bone

Question 1

What type of cells are cartilage and bone derived from

Answer 1

undifferentiated mesenchymal cells in the embryo

Question 2

What are the precursors of cartilage

Answer 2

Mesenchymal cells differentiate into chondroblasts which future differentiate into chondrocytes

Question 3

What is mature cartilage composed of

i.e. cells, matrix, capsule

Answer 3

Cells - chondrocytes
Matrix - a dense glycosaminoglycan rich substance containing collagen and elastic tissue
Capsule - Fibrous collagen capsule known as the perichondrium

Question 4

What are the 3 different forms of cartilage

Answer 4

Fibrous, elastic and hyaline

Question 5

Where is hyaline cartilage found

Answer 5

supporting ‘rings’ of trachea

cartilage of the larynx

Question 6

Where is elastic cartilage found

Answer 6

Epiglottis

Pinna of the ear

Question 7

Where is fibrous cartilage found

Answer 7

Inter-vertebral discs

Question 8

What does ‘GAG’ stand for

Answer 8

Glycosaminoglycan

Question 9

In hyaline cartilage, what is the name of the pale staining hollows that chondrocytes are found within

Answer 9

lacunae

Question 10

What happens when hyaline cartilage is compressed

Answer 10

It exudes water

Question 11

Do chondrocytes clump or appear singularly within the matrix

Answer 11

usually clump

Question 12

Which types of cartilage can you fracture

Answer 12

All of them!

Question 13

How is bone synthesised

Answer 13

Osteoblasts synthesis a collagen rich matrix called osteoid. This mixes with crystals of hydroxyapetite to form osteocytes

Question 14

What is the function of osteoclasts (cells also found in the bone)

Answer 14

continuous remodelling of bone throughout life

Question 15

What is found in the centre of many layers of osteons making up bone

Answer 15

Haversian’s canal

Question 16

What is found within Haversian’s canal

Answer 16

blood vessels and nerves

Question 17

What is interstitial bone and where is it found

Answer 17

Between osteons. It is old, dead bone

Question 18

What are bones surrounded with

Answer 18

A fibrous capsule called periosteum - contains undifferentiated cells, important in bone healing

Question 19

What is the average size of an osteon (may only be applicable to single slide..)

Answer 19

220 um

Question 20

What is a cement line

Answer 20

Surrounds an osteon. It seals off the osteon from surrounding neighbours

Question 21

What is the role of filopodia

Answer 21

They make contact with adj. cells - movement of nutrients and oxygen

Question 22

Why are some Haversian Canal’s larger than others

Answer 22

bone becomes thinner with age

Before new bone is formed and as older phone dies the canal widens

Question 23

Most bone was once cartilage. What is the name of the process of direct differentiation into bone from mesenchyme

Answer 23

intra-membranous ossification

Question 24

Why do osteoblasts stain dark purple with H&E

Answer 24

Because the cytoplasm contain ++nucleic acid (RNA)

Question 25

What happens to osteoblasts when they have completed their task of laying down new bone

Answer 25

They are trapped within new bone and transform into osteocytes

Question 26

What are osteoclasts and where do they differentiate from

Answer 26

They are macrophages and they differentiate from blood monocytes. They digest bone and allow it to be remodelled - allowing the release of Ca+ into the circulation. They are completely separate to osteoblasts and cytes

Question 27

How can you distinguish osteoclasts from blasts

Answer 27

greater size, multi-nuclear, intense pink staining cytoplasm

Question 28

Where are osteoclasts found

Answer 28

In depressions know as Howship's lucunae

Question 29

Why do osteoclasts stain intense pink

Answer 29

They contain lysosomal enzymes

Question 30

What is mature cartilage composed of | i.e. cells, matrix, capsule

Answer 30

Cells - chondrocytes Matrix - a dense glycosaminoglycan rich matrix containing collagen and elastic tissue Capsule - Fibrous collagen capsule known as the perichondrium

Question 31

Why are some Haversian Canal's larger than others

Answer 31

bone becomes thinner with age | Before new bone is formed and as older bone dies the canal widens

Question 32

How does hyaline cartilage receive its nutrients and oxygen

Answer 32

mostly by diffusion

Question 33

What is the difference between the interior heads of the bone and the shaft of the bone

Answer 33

They have identical composition but the heads have large holes to decrease the overall weight of the bone

Question 34

Once embedded in the matrix, can chondrocytes divide

Answer 34

Yes

Question 35

What do osteoblasts synthesise

Answer 35

osteocalcin

Question 36

What does Volkmann's Canal do

Answer 36

It joins adj. osteons