Calcium & Bone

Question 1

what is the periodontium

Answer 1

tissue around the tooth

Question 2

what does the periodontium compromise of

Answer 2

PDL
alveolar bone
gingiva (gum- incl junctional epi)
—- Cementum?

Question 3

what are the functions of bone

Answer 3

skeletal

• protection organs
• rigidity
• movements
• attach muscles and teeth

calcium pool
contain marrow

Question 4

why is it imp to know about bone

Answer 4

regional diff in mouth - LA
bone changes in mouth - extraction
ortho tooth moves
osseointegration - implants
biphosphonates

Question 5

what is the composition of bone

Answer 5

65% mineral - HA
25% organic - 90% type 1 collagen an 10% ground subs
10% water

Question 6

what is the alveolus

Answer 6

sac

little cavity

Question 7

what are the components of the alveolar bone

Answer 7

alv bone - cortisol bone compact

basal bone - trabecular bone spongy and cancellous

Question 8

what is the lamina dura

Answer 8

budnelbone
cribriform plate
lining alveolus tooth sits in

Question 9

what are the lamellae assc with bone

Answer 9

circumferential
concentric
interstitial

Question 10

what are the circumferential lamellae

Answer 10

outside of most cortisol bone

Question 11

what are the concentric lamellae

Answer 11

organised in haversian system s- osteon

Question 12

what are the interstitial lamellae

Answer 12

remnants of old lamellae

Question 13

what are the means of bone formation

Answer 13

endochondrol ossification

intramembranous ossification

Question 14

what is endochondral ossify

Answer 14

cartilage –> calcified cart –> bone

Question 15

what is intramembranous oddification

Answer 15

cold of mesenchymal tissue
osteoblasts prod osteoid matrix
woven bone
primary osteon form

Question 16

what are osteoblasts

Answer 16

mesenchymal/ectomesnchymal
bone surface - periosteum/endosteum
prod osteoid matrix

Question 17

what are osteocytes

Answer 17

trapped osteoblasts
cell processes
linked by gap junctions
cells vital

Question 18

what are osteoclasts

Answer 18

haemopoeitic source - macrophage
large multinuc cells
in how ships lacunae - dissolve bone mineral - acid and break org matrix with enzymes

Question 19

how freuwnet is bone turnover

Answer 19

continuous remodelling
resoprton
deposition

Question 20

when is bone completely replaced

Answer 20

every 10 years

helps maintain plasma calcium levels

Question 21

how si bone remodelled

Answer 21

cutting cone - osteoblasts

filling cone - osteoblasstst

Question 22

what does remodelling result in

Answer 22

secondary osteons etc

Question 23

how much calcium in body

Answer 23

1kg
99% in bone and teeth
1% body fluids

Question 24

what are roles of calcium

Answer 24

mem perm
excitation - contraction
excitation  - secretion
hard tissue form 
blood clots
enzyme rctaion 
in secretions - milk

Question 25

what is quick regulation of calcium regulation

Answer 25

rapid exchanges between bone and ECF

Question 26

what is slow regulation go calcium

Answer 26

intestinal abs | renal excretions

Question 27

what is parathyroid hormone

Answer 27

``` essential for life release in response o falling Ca increases plasma corn of calcium prevents hypocalcaemia withdraws calcium from bone bank ```

Question 28

what si the mechanism of PTH

Answer 28

``` fast Ca efflux to plasma - osteocytes from labile pool of Ca slow Ca efflux to plasma - bone dissolution - shift remodelling to favour resorption - osteoclasts kidney - reduced excrete of Ca ```

Question 29

what does pTH deficiency lead to

Answer 29

iatrogenic PT gland tetany asphyxiation

Question 30

what does PT hormone excess lead to

Answer 30

hyperplasia of PT gland tumours weak bones ectopic mineralisation

Question 31

what is calcitonin form

Answer 31

c cells on thyroid gland

Question 32

what does calcitonin do

Answer 32

prevents calcium conc in plasma becoming high

Question 33

how does calcitonin work

Answer 33

reduce osteocyte and osteoclast activity | reduce osteoclast numbers

Question 34

what is vitamin d essential for in tim of Ca

Answer 34

Ca in intestine

Question 35

what is vit d

Answer 35

prod in skin in response to sunlight on a precursor | increases Ca abs in intestine

Question 36

what is BRONJ

Answer 36

biphsophonate related osteonecrosis of the Jaws

Question 37

what are bisphosphonates used for

Answer 37

osteoporosis reduce rates | bone metastases

Question 38

hwodoes Bisphophonates work

Answer 38

reduce osteoclast activity and reduce bon breakdown

Question 39

what doe BRONJ do

Answer 39

impaired bone turnover --> exposed bone after extraction