Anatomy and composition of bone & cartilage

Question 1

Compact bone is also known as

Answer 1

Cortical bone

Question 2

What is the anatomical name for the bone’s shaft?

Answer 2

Diaphysis

Question 3

Metaphysis

Answer 3

flared region of the long bone adjacent to the epiphysis

Question 4

Epiphysis

Answer 4

rounded end of the long bone

Question 5

Cancellous bone is also known as

Answer 5

trabecular or spongy bone

Question 6

Bones can be classified by

Answer 6

• where they occur
• how they form
• what shape they are

Question 7

How to classify bones based on where they occur

Answer 7

• Axial skeleton
• Appendicular skeleton
• Visceral bones

Question 8

Axial skeleton

Answer 8

Bones that form the axis of the skeleton e.g. bones of head, neck, vertebral column, ribs, pelvis, tail

Question 9

Appendicular skeleton

Answer 9

Regions that are attached e.g. bones of the forelimbs and hindlimbs

Question 10

Visceral bones

Answer 10

Bones that develop in the soft tissues away from the rest of the skeleton.

Question 11

Types of bones (shape)

Answer 11

• Long bones
• Short bones
• Flat bones
• Irregular bones
• Sesamoid bones
• Pneumatic bones

Question 12

What is the periosteum?

Answer 12

Bone producing membrane: fibrous on outside, cellular on inside

Useful for membranous ossification

Provides blood supply for and protects actively growing bone

Question 13

What is interstitial growth?

Answer 13

Internal expansion

Question 14

How do bone and cartilage differ in terms of growth?

Answer 14

Cartilage can undergo interstitial expansion which bone cannot.

Question 15

Vasculature of cartilage

Answer 15

Cartilage is avascular

Question 16

Innervation of cartilage

Answer 16

Cartilage is aneural

Question 17

Types of cartilage

Answer 17

• Hyaline/articular
• Fibrocartilage (white cartilage)
• Elastic (yellow cartilage)

Question 18

What can be said about the types of cells that exist within different cartilage types?

Answer 18

All cartilage types contain chondrocytes.

Hyaline and elastic contain chondroblasts also.

Fibrocartilage contain fibroblasts.

Question 19

When bone is laid down, two types form one after the other. What are they?

Answer 19

• Woven bone: random orientation of collagen fibres, laid down first & quickly; immature
• Lamellar bone: organisation of collagen fibres, laid down second; mature

Question 20

What are osteoprogenitor cells and what is their function?

Answer 20

Mesenchymal cells located in the bone.

Capable of self-renewal, proliferation, osteogenic differentiation.

Secrete bone matrix.

Question 21

What is the function of osteoblasts?

Answer 21

Role in bone formation

Secrete Type 1 collagen and bone matrix proteins

Question 22

What are the histological featurs of osteoblasts?

Answer 22

Cuboidal and polygonal cell shapes

Question 23

What are osteocytes?

Answer 23

Once osteoblasts have been surrounded by ECM, they become known as osteocytes.

Question 24

What is the role of osteocytes?

Answer 24

Can participate in matrix degradation

Question 25

What are the histological features of osteocytes?

Answer 25

Sit within lacunae Have interconnecting canaliculi

Question 26

What are osteoclasts and what is their function?

Answer 26

Cells involved in bone resorption Present where bone is being removed, remodelled or damaged \*originate from different cell type to other bone cells\*

Question 27

What are the histological features of osteoclasts?

Answer 27

Multinucleate cells

Question 28

Structure of periosteum

Answer 28

Fibrous on the outside - dense connective tissue Cellular on inside - osteoprogenitor cells

Question 29

Describe the functional adaptatios of the long bone

Answer 29

* Cortical bone provides rigidty, resists compression * Expanded ends enable transfer of load * The bone acts as a lever, resisting tension during muscle contraction

Question 30

What is the function of the medullary cavity?

Answer 30

Source of mesenchymal stem cells

Question 31

What is the endosteum?

Answer 31

Thin vascular membrane of connective tissue; lines the medullary cavity

Question 32

What is the function of tubercles, trochanters and tuberosities?

Answer 32

Muscle/ligament/tendon attachment

Question 33

What is the function of fossae?

Answer 33

Positioning and seating for ligaments

Question 34

What is the function of condyles and epicondyles?

Answer 34

Articulation and muscle/tendon/ligament attachment

Question 35

What does this image show?

Answer 35

The general structure of hyaline cartilage

Question 36

Describe the circled structure

Answer 36

Chondrocytes stained with an H&E stain There are two chondrocytes in an isogenous group They have pale cytoplasm and darkly staining nuclei Between the two cells and in a small radius around them the background is darker staining than in the rest of the image, indicating territorial matrix

Question 37

What type of cartilage is shown in this image?

Answer 37

Hyaline

Question 38

What is the function of hyaline cartilage?

Answer 38

* Resist compression * Provide cushioning * Smooth, low-friction surface for joints * Structural support (e.g. respiratory system) * Precursor to bone in embryonic skeleton * Centre of chondral ossification * Withstands and distributes load

Question 39

What types of cells does hyaline cartilage contain?

Answer 39

Chondroblasts Chondrocytes

Question 40

What does the ECM of hyaline cartilage contain?

Answer 40

Type II collagen fibrils Aggrecan monomers

Question 41

Which types of cartilage undergo calcification?

Answer 41

Hyaline and fibrocartilage NOT ELASTIC

Question 42

When does hyaline cartilage undergo calcification?

Answer 42

In endochondral bone formation During the aging process

Question 43

Perichondium

Answer 43

Connective tissue that envelops cartilage when it is not at a joint

Question 44

Is there a perichondium present in hyaline cartilage?

Answer 44

Yes but not at articular cartilage or epiphyseal growth plates

Question 45

Where is hyaline cartilage found?

Answer 45

* Foetal skeletal tissue * Epiphyseal plates * Synovial joints * Costal cartilage * Rings of trachea

Question 46

What is the function of elastic cartilage?

Answer 46

* Provides flexible support for soft tissues * Structural support - keeps tubes open but flexible

Question 47

What cells does elastic cartilage contain?

Answer 47

Chondroblasts Chondrocytes

Question 48

What does the elastic cartilage ECM contain?

Answer 48

Type II collagen fibrils Elastic fibres Aggrecan monomers

Question 49

Does elastic cartilage undergo calcification?

Answer 49

NO

Question 50

Is a perichondium present in elastic cartilage?

Answer 50

Yes

Question 51

Where is elastic cartilage found?

Answer 51

* Pinna of external ear * Eustachian canals * Larynx

Question 52

What is the function of fibrocartilage?

Answer 52

* Resists deformation under stress * Tough support: provides great tensile strength * Ligament/tendon and bone interface; lines surface of bony grooves for tendon

Question 53

What cells does fibrocartilage contain?

Answer 53

Fibroblasts Chondrocytes

Question 54

What does the ECM of fibrocartilage contain?

Answer 54

* Type I and II collagen fibres * Proteoglycan monomers: aggrecan and versican

Question 55

When does calcification of fibrocartilage occur?

Answer 55

Calcification of fibrocartilage callus occurs during bone repair

Question 56

Is a perichondium present in fibrocartilage?

Answer 56

No

Question 57

Where is fibrocartilage found?

Answer 57

* Intervertebral discs * Pubic symphysis * Articular discs * Menisci * Insertion of tendons

Question 58

What is the name of this feature?

Answer 58

Osteon: concentric bone rings surrounding a Haversian canal.

Question 59

What is the name of this feature?

Answer 59

Haversian canal

Question 60

What is the name of this feature?

Answer 60

Lacuna

Question 61

What is the name of this feature?

Answer 61

Canaliculis (pl. canaliculi)

Question 62

What is this feature called? What does it contain?

Answer 62

Haversian canal Contains blood vessels, nerves, lymphathics

Question 63

What are these features called? What do they contain?

Answer 63

Canaliculi Contain cytoplasmic processes of osteocytes

Question 64

What is this feature called? What does it mark?

Answer 64

Cement line It markes the boundary of an osteon

Question 65

Discuss the differences between bone and cartilage

Answer 65

* Bone has a vascular and neural supply whereas cartilage is avascular and aneural * Cartilage is able to undergo interstital expansion but bone cannot * Cartilage is still capable of dividing in the matrix; bone cannot divide once surrounded by matrix * Bone contains mostly Type I collagen, cartilage contains mostly Type II (1 in fibrocartilage)