Bone and Cartilage

Question 1

what are the 2 types of bone?

Answer 1

cortical, compact bone and cancellous, spongy bone

Question 2

where is the cortical bone?

Answer 2

it is the dense outer plate

Question 3

where is the cancellous bone?

Answer 3

it is the internal trabecular scaffolding

Question 4

what is the alveolar bone structure like?

Answer 4

cortical bone which has nutrient canals containing blood vessels

Question 5

what is the cortical bone lining of the alveolar bone penetrated by?

Answer 5

bundles of collagen fibres of PDL

Question 6

what does the inorganic component of bone consist of?

Answer 6

hydroxyapatite

Question 7

what does the organic component of bone consist of?

Answer 7

collagen, glycoproteins, proteoglycans

Question 8

what is ground substance

Answer 8

semi fluid gel made of long polysaccharide molecules and glycos-amino-glycans

Question 9

which types of GAGs make up the ground substance?

Answer 9

hyaluronic acid, proteoglycans

Question 10

what are the proteoglycans in bone?

Answer 10

chondroitin sulphate, dermatan sulphate, heparan sulphate, keratan sulphate

Question 11

what is the function of the fibres in the extracellular matrix?

Answer 11

to reinforce extracellular ground substance

Question 12

what types of fibres are found in the ECM?

Answer 12

collagen, elastin and other non-collagenous proteins

Question 13

microscopically, what are the different types of bone (not cortical/cancellous)

Answer 13

woven and lamellar

Question 14

what is woven bone and where is it present?

Answer 14

irregular deposition of collagen present in foetus and fracture repairs

Question 15

what type of cell does woven bone have many of?

Answer 15

osteocytes

Question 16

which type of bone is rapidly laid down?

Answer 16

woven bone

Question 17

what is lamellar bone and where is it present

Answer 17

collagen fibres laid down in parallel in adults

Question 18

what type of bone is laid more slowly?

Answer 18

lamellar bone

Question 19

what type of bone contains fewer osteocytes?

Answer 19

lamellar bone

Question 20

what type of structure is compact bone laid down in?

Answer 20

concentric lamellae which forms longitudinal columns

Question 21

what type of system is compact bone organised in?

Answer 21

haversian systems around a central haversian canal

Question 22

what type of canals link the Hversian canals?

Answer 22

Volkmans canals

Question 23

what do the canals contain

Answer 23

blood vessels

Question 24

what are Haversian systems also called?

Answer 24

osteons

Question 25

what does an osteon look like?

Answer 25

central small lacunae with radiating canaliculi (small canals)

Question 26

what is cancellous bone

Answer 26

a network of thin trabeculae

Question 27

what do trabeculae consist of?

Answer 27

lamellae

Question 28

does cancellous bone have a Haversian system?

Answer 28

no

Question 29

instead of having a Haversian system how do nutrients get about cancellous bone?

Answer 29

the bone is thin so the nutrients can diffuse in

Question 30

what is present between trabeculae?

Answer 30

bone marrow

Question 31

where do osteoblasts lie?

Answer 31

on surface of bone

Question 32

what are osteoblasts derived from

Answer 32

mesenchymal stem cells

Question 33

what do osteoblasts do?

Answer 33

synthesise and secrete collagen fibres forming a matrix

Question 34

what is the matrix secreted by osteoblasts mineralised by?

Answer 34

calcium salts

Question 35

what are osteocytes

Answer 35

osteoblasts which are trapped in mineralised bone

Question 36

where do osteocytes lie?

Answer 36

in spaces (lacunae)

Question 37

how do osteocytes contact each other?

Answer 37

via cytoplasmic processes that run in canaliculi

Question 38

what are osteoclasts?

Answer 38

large multinucleated cells derived from haemopoietic stem cells

Question 39

what do osteoclasts do?

Answer 39

resorb bone

Question 40

where do osteoclasts lie?

Answer 40

in concavities in the bone - Howships lacunae

Question 41

what is bone remodelling

Answer 41

removal and replacement of bone tissue without change in overall shape

Question 42

what percentage of cortical bone is replaced per year?

Answer 42

2%

Question 43

what percentage of cancellous bone is replaced per year?

Answer 43

25%

Question 44

what is bone remodelling controlled by?

Answer 44

osteoblasts

Question 45

what is bone remodelling regulated by?

Answer 45

hormones (PTH, calcitonin), paracrines (cytokines)

Question 46

how does bone turnover work?

Answer 46

PTH secretes collagenase and osteoclasts to start the process of bone resorption, osteoblasts produce osteoids whilst this is occurring

Question 47

what is a reversal line?

Answer 47

scalloped edge which shows where bone resorption changes to bone deposition

Question 48

what does tooth movement require?

Answer 48

remodelling of adjacent soft and hard tissues

Question 49

when does tooth movement take place?

Answer 49

during eruption, post-eruptive (mesial drift), orthodontic forces

Question 50

what is cartilage?

Answer 50

semi-rigid unmineralised connective tissue

Question 51

what type of matrix does cartilage have?

Answer 51

a similar one to bone consisting of ground substance and fibres

Question 52

what are the 3 types of cartilage?

Answer 52

hyaline cartilage, fibrocartilage and elastic cartilage

Question 53

give examples of where hyaline cartilage is present

Answer 53

larynx, nasal septum, trachea

Question 54

give examples of where fibrocartilage is present

Answer 54

intervertebral discs

Question 55

give examples of where elastic cartilage is present

Answer 55

external ear, epiglottis

Question 56

what are cartilage cells formed by?

Answer 56

chondroblasts

Question 57

what do chondroblasts become once they get trapped in cartilage matrix?

Answer 57

chrondrocytes

Question 58

what do chondrocytes contain?

Answer 58

stores of lipid and glycogen

Question 59

what are the 2 types of bone growth?

Answer 59

endochondral ossification and intramembranous ossification

Question 60

which type of bones use endochondral ossification

Answer 60

long bones of which cartilage had been laid down as a precursor

Question 61

which type of bones use intramembranous ossification?

Answer 61

flat bones with no cartilage precursor

Question 62

where does cartilage proliferation and growth occur?

Answer 62

at the epiphyses

Question 63

which type of ossification does the spheno-occipital bone have?

Answer 63

both as it is the face of the skull so it does not have flexibility of the parietal, frontal and occipital bone

Question 64

what type of ossification is affected by achondroplasia?

Answer 64

endochondral

Question 65

which type of ossification does the condyle have?

Answer 65

endochondral as it changes shape from birth to elderly

Question 66

why does the angular process of the mandible change shape?

Answer 66

because it needs teeth to maintain shape and if teeth are lost the bone will resorb