Bone

Question 1

intramembranous ossification

Answer 1

(where bone forms directly within
a vascular connective tissue,

Question 2

endochondral ossification

Answer 2

bone is preceded by a cartilaginous model
that is eventually replaced by bone

Question 3

bundle bone

Answer 3

a thin layer of compact, cortical bone lines the tooth socket

Question 4

which bone gives
attachment to the principal fibres of the periodontal ligament.

Answer 4

bundle bone

Question 5

lamellar or woven bone has larger and more numerous osteocytes

Answer 5

woven

Question 6

where is Woven bone seen

Answer 6

sites of fracture repair or in
healing tooth sockets.

It mineralises faster than adult bone so that there
is no lag phase and it is more mineralised. Woven bone is subsequently
replaced by fne-fbred adult lamellar bone.

Question 7

what % of skeleton is cortical bone

Answer 7

80-85%

Question 7

bone composition

Answer 7

Bone is a mineralised connective tissue. About 60% of its wet weight is
inorganic material, about 25% organic material and about 15% water.

Question 8

appearance of inner cortical bone

Answer 8

sieve like, nutrient canals containing blood vessels, penetrated by bundles of sharpeys fibres

Question 9

ECM of bone

Answer 9

semi fluid gel
long polysaccharide moleucules
GAGs

Question 10

What fibres in bone

Answer 10

collagen
elastin

Question 11

what proteins in bone

Answer 11

glycoproteins
- osteocalcin
-osteonectin
-osteopontin
-sialoproteins

proeteoglycans

Question 12

what are the proteins in bone important for ie function

Answer 12

osteonectin and osteopontin can be use to induce bone repair

Question 13

woven bone vs lamellar bone in term of speed, arrangement, in who and what type of cells

Answer 13

woven
rapid
irregular
fetus
fracture
many osteocytes

lamellar
slow
parallel collagen fibres
adult
fewer osteocytes

Question 14

osteoid

Answer 14

unmineralized matrix of bone

Question 15

what is mineralisation of osteoid dependent on

Answer 15

vitamin D active

Question 16

is haversian or volkmanns canals horizontal

Answer 16

volkmanns are lateral

haversian are the main ones , longitudinal

Question 17

how is compact bone formed

Answer 17

laid down in concentric lamellae

Question 18

can volkmann canals cross the lamellar bone?

Answer 18

yes, they can appear on the external surface of bone

in this case, it appears on the internal surface of the tooth socker (cribriform plate)

Question 19

where do osteocytes lie

Answer 19

lacunae

Question 20

canaliculi

Answer 20

cytoplasmic processes of osteocytes for communicating

Question 21

what is compact bone made of

Answer 21

lamellar bone

Question 22

what is cancellous bone made of

Answer 22

primarily composed of lamellar bone, but it has a different structural arrangement compared to compact bone.

In trabecular bone, lamellae (layers of bone tissue) are arranged in a lattice-like or trabecular pattern, forming a network of interconnected struts or trabeculae. This network creates spaces between the trabeculae, which are filled with bone marrow and blood vessels.

Question 23

diff between cancellous and compact bone

Answer 23

Cancellous (Trabecular or Spongy) Bone:
- no haversian systems,
- bone is thinner for diffusion
- epiphysis of long bones, and
- in the interior of other bones.

Compact (Cortical) Bone:
- Haversian
- outer layer (cortex) of all bones

Question 24

where are osteoblasts located

Answer 24

surface of bones

Question 25

osteoblasts are derived from what

Answer 25

mesenchymal stem cells

Question 26

what osteoblasts do

Answer 26

secrete collagen forming an unmineralised matrix which is later mineralised

Question 27

osteoclasts are derived from what

Answer 27

macrophages

Question 28

what does osteoclast produce

Answer 28

acid phosphatases that resorb bone

Question 29

where are osteoclasts located

Answer 29

howships lacunae

Question 30

what is bone remodelling

Answer 30

removal and replacement of bone tissue without change in overall shape

Question 31

what cell controls bone remodelling

Answer 31

osteoblasts
produces OPG and RANKL

Question 32

what regulates bone remodelling

Answer 32

hormones PTH and calcitonin
paracrines

Question 33

function of PTH and calcitonin

Answer 33

PTH stimulates bone resorption (the breakdown of bone tissue) by activating osteoclasts, cells responsible for breaking down bone.

Calcitonin has an opposing effect to PTH. It inhibits bone resorption by osteoclasts, slowing down the breakdown of bone tissue.

Question 34

reversal line

Answer 34

change from resorption to deposition

rich in osteopontin and acid phosphatase

Question 35

where is there alot of bone remodelling in mouth

Answer 35

eruption
post eruptive mesial drift
orthodontic forces

Question 37

long bone made by what ossification

Answer 37

Long bone mad3 by Endochondral

Flat bone made by Intramembranous