histology Flashcards
1
Q
bone
A
highly specialized calcified CT rich in blood supply
2
Q
functions of bone
(5)
A
skeleton
attachment media
protects vital organs
reservoir for minerals
formation of blood cells
3
Q
composition of bone
(2)
A
inorganic (67%)
organic & water (33%)
4
Q
inorganic substances (67%)
(2)
A
- mostly calcium and phosphate
- causes hardness of bone
5
Q
organic substances (33%)
(2)
A
- 28% collagen fibers
- 5% ground substances
6
Q
5% ground substances components
(3)
A
glycosaminglycan (GAG)
glycoprotein
phosphoprotein
7
Q
bone structure
(2)
A
periosteum & endosteum
8
Q
periosteum def
(hint: 2 layers) (2)
A
- lines the outer surface of compact bone
- 2 layers (outer fibrous & inner cellular)
9
Q
sharpeys fibers are collagenous fibers from…
A
outer layer of periosteum which insert into bone to firmly attach periosteum to bone
10
Q
endosteum def
(hint: lines what) (3)
A
- lines inner surface of compact bone
- lines haversian canals
- surrounds surface of spongy bone
11
Q
functions of peri & endo
(2)
A
- contain blood vessels for nutrition
- source of osteoblasts
12
Q
bone cells :
(4)
A
- osteoprogenitor (osteogenic)
- osteoblasts
- osteoclasts
- osteocytes
13
Q
osteogenic
(2)
A
- mitotically active stem cells
- differentiate into osteoblasts
14
Q
osteoblasts
(3)
A
- bone forming cells
- secrete unmineralized bone matrix called osteoid
- actively mitotic
15
Q
osteoid
(2)
A
- made of collagen & calcium binding proteins
- later hardens into bone
16
Q
osteocytes
(4)
A
- in lacunae & dont divide
- maintain matrix, & act as stress sensors
- respond to mechanical stimuli
- communicate info to osteoblasts & osteoclasts
16
Q
bone lining cells
(4)
A
- flat cells on bone surface
- help maintain matrix
- peri = external
- endo = internal
17
Q
osteoclasts
(4)
A
- from hematpoietic stem cells that become macrophages
- giant multinucleated resorbing cells
- located in howships lacunae
- ruffled borders for enzyme degradation
18
Q
types of bones
(3)
A
non- lamellar
lamellar
bundle bone
19
Q
non-lamellar bone
(4)
A
- found in fetal life, extraction socket & fratures
- lots of osteocytes
- irregular & less mineralized
- temporary
19
Q
lamellar bone types
(2)
A
- compact
- spongy
20
Q
compact lamellar bone
(hint: 3 types) (4)
A
- very dense, no marrow space
- has 3 types:
- circumferential
- haversian
- interstitial
21
Q
haversian lamellae
(4)
A
- arranged in 4-20 lamellae rings (haversian system)
- has b.v, nerves, C.T. & lined by endosteum
- connected to each other by volkmans cannals
- connected to osteocytes & haversian canals by canaliculi
21
Q
circumferential lamellae
(2) (forms what…)
A
- adjacent to periosteum & endosteum
- forms external & internal lamination of cortical bone
22
interstitial lamellae
| (3)
- parallel lamellae
- randomly scattered
- remnants of haversian & circumferential
23
spongy bone
| (3) (why is it spongy)
- spongy due to trabeculae & marrow spaces
- marrow between trabeculae
- few osteons(haversian systems), NO central canals
24
incremental lines of lamellar bone
| (3)
- faint
- resting
- reversal
25
bundle bone
lining of socket wall where sharpeys fibers from the PDL attach the tooth to the bone
26
alveolar process of maxilla & mandible
jaw bones which contain & support the alveoli (sockets) of the erupted teeth
27
development stages of the alveolar process
| (3)
1. STARTS near end of 2nd month of pregnancy (MIU)
2. DURING eruption alveolar process develops
3. AFTER eruption alveolar bone slowly takes adult form
28
macro & micro anatomy of alveolar process
| (2 types of bone)
- alveolar bone proper (bundle bone, lamellar bone)
- supporting alveolar bone ( cortical plates, spongy bone)
29
alveolar bone proper
| (5)
- from osteoblasts (derived from dental sac)
- provides medium for attachment of PDL fibers
- lamina dura (same as bundle bone)
- have zuckerkandl & hirshfeld canals (allows nerve, b.v to reach PDL)
- ALSO CALLED CRIBRIFORM
30
quick reminder:
- Alveolar bone proper = the entire bone lining the tooth socket.
- Bundle bone = the specific part of alveolar bone proper where Sharpey's fibers anchor.
31
bundle bone
| (3)
- adjacent to PDL
- bundles of woven bone
- insertion of PDL fibers
32
lamellated bone
| (2)
- adjacent to bundle bone
- parallel to marrow spaces
33
cortical plates
| (5)
- forms inner & outer plates (labial & lingual)
- thinner in maxilla
- thickest in mand premolar & molar
- anterior supporting bone is very thin, & NO spongy bone
- haversian system (the pipes) and longitudinal lamellae (the bricks) make up the cortical plates (brick wall)
33
Supporting Alveolar bone
| (hint: split into 2 things) (4)
- surrounds alveolar bone proper
- supports sockets of tooth
split into:
- cortical plates of compact bone
- spongy bone between cortical plates
34
spongy bone
- between cortical & alveolar bone proper
35
Locations of spongy bone :
| (4)
1. cancellous bone
2. around teeth subjected to high forces
3. type 1 & type 2
4. trabeculae of root apex of lower molars
35
type 1 spongiosa :
| (3)
- regular
- horizontal
- ladder like arrangement (ONLY in mandible)
36
type 2 spongiosa :
| (3)
- irregular
- numerous
- delicate (common in maxilla)
37
physiological changes of alveolar process :
| (4)
1. internal structure adapted to mechanical stress
2. changes continuously during growth
3. correlated to(5):
- eruption & growth
- movements
- wear & loss of teeth
4.structural changes occur by coordination between formative & destructive activities
38
bone formation is by:
osteoblasts
39
bone resorption is by:
osteoclasts
