Skeletal System Part 2 Flashcards
1
Q
Concentric bony lamellae laid down by successive layers of
A
osteoblasts
2
Q
Osteoblasts become trapped in lacunaein osteoid matrix & mature into
A
osteocytes
3
Q
Osteocytes connected by minute canals (canaliculi) containing — —
A
cytoplasmic extensions
4
Q
canaliculi communicate with each other via
A
gap junctions
5
Q
Within center of each osteon is
A
Haversian canal (canal of Havers)
6
Q
Haversian canal contains (2)
A
blood vessels & Nn
7
Q
Longitudinal Haversian canals are connected by
A
transverse Volkmann’s canals
8
Q
Exchange of waste & nutrients occurs via
A
Haversian vessels
9
Q
Haversian systems oriented parallel to
A
long axis of bone
10
Q
Inactive Haversian systems known as
A
interstitial systems
11
Q
Spongy & woven bone lack
A
Haversian system
12
Q
Haversian system is present only in
A
compact lamellar bone
13
Q
Outer periphery of cortical bone arranged in
A
circumferential lamellae
14
Q
Covered by dense connective tissue called
A
periosteum
15
Q
bone growth is controlled by (3)
A
growth hormone, thyroid hormone, & sex hormones
16
Q
Endochondral ossification
A
replacement of cartilage precursor by bone
17
Q
Resulting woven bone is extensively remodeled by (2)
A
resorption & appostional growth
18
Q
resorption & appostional growth result in =
A
lamellar bone (e.g., long bones, vertebrae, pelvis, & base of skull)
19
Q
Intramembranous ossification
A
direct replacement of mesenchyme by bone
20
Q
in intramembranous ossification there is no — precursor
A
no cartilage precursor
21
Q
Mesenchymal cells differentiate into —, produce —, later mineralizes into —
A
osteoblasts
osteoid
bone (e.g., vault of skull)
22
Q
Precursor of long bone formed of
A
hyaline cartilage
23
Q
1’ center of ossification occurs in
A
mid-diaphysis
24
Q
Osteoprogenitor cells and osteoblasts secrete osteoid, which mineralizes, forming
A
periosteal cuff
25
Calcification of cartilage matrix inhibits diffusion of nutrients resulting in (2)
death of chondrocytes & spread of osteoblasts
26
Osteoprogenitor cells from periosteum migrate into ---, along with --- --- ---
medulla
| growing blood vessels
27
Two 2’ centers of ossification occur in
epiphyses
28
mineralization spreads across
cartilage matrix
29
Epiphyseal plate in region of metaphysis remains “---” (i.e., unmineralized)
open
30
Allows continuous
longitudinal growth
31
At maturity, hormonal changes decreases --- --- & cartilage plate is replaced by ---
cartilage proliferation
| bone
32
what does the epiphyseal growth plate consist of
several distinct zones in transition from cartilage to bone
33
Zone of Reserve Cartilage
hyaline cartilage with clusters of chondrocytes
34
proliferation in zone of reserve cartilage
no cell proliferation
35
Zone of Proliferation
successive mitotic division of chondrocytes, which results in columns of chondrocytes
36
Zone of Maturation
division ceases
37
in the zone of maturation, chondrocytes...
increase in size
38
Zone of Hypertrophy (& Calcification) (3)
chondrocytes greatly enlarge, contain large amounts of glycogen, become vacuolated & calcify
39
Zone of (Cartilage) Degeneration
capillaries of marrow cavity grow from diaphysis into growth plate
40
in the zone of degeneration, chondrocytes degenerate; lacunae invaded by
osteogenic cells
41
Zone of Ossification
blood vessels from marrow cavity grow into cartilage mass
42
Osteogenic cells differentiate into osteoblasts, congregate on spicules of calcified cartilage matrix to form bony
trabeculae
43
Mesenchymal cells differentiate directly into
osteoblasts
44
mesenchymal cells begin synthesizing osteoid at multiple sites, (multiple centers of ossification) within
membrane—no cartilage precursor
45
Mineralization follows with subsequent fusion of adjacent
centers of ossification
46
Osteoblasts trapped within lacunae of osteoid, become
osteocytes
47
Osteoprogenitor cells at periphery continue to divide, provide
replacements
48
Bone produced is woven bone—later remodeled by osteoclasts & osteoblasts to form
compact bone
49
Simple or closed fracture
no break in skin
50
Compound or open fracture
damage to skin exposing bone
51
Comminuted fracture
bone broken in several pieces
52
Blood fills fracture site, resulting in
hematoma
53
immediately after fracture, inflammatory response develops—(4)
pain, swelling, redness, & heat
54
In acute phase (first few days) --- first to arrive, infiltrate hematoma, then ---, (both phagocytic) to clean up site of injury
neutrophils
| macrophages
55
After ~1 wk, (2) proliferate & grow into site
fibroblasts & capillaries
56
bone repair forms
granulation tissue (vascular collagenous tissue)
57
granulation tissue becomes progressively more fibrous in chronic phase, forms
fibrous granulation tissue
58
Mesenchymal cells differentiate into chondroblasts, secrete
matrix
59
matrix secretion results in progressive replacement of granulation tissue by
hyaline cartilage
60
progressive replacement of granulation tissue by hyaline cartilage
provisional callous
61
Next, osteoprogenitor cells & osteoblasts from endosteum & periosteum at edge of wound grow ---
inward
62
produce meshwork of woven bone within provisional callous, deposit calcium salts in
collagen matrix
63
Transforms into
bony callous
64
bony callous helps (2) fracture together
stabilize & bind fracture together
65
Important to realign & stabilize, or “set” fracture --- this happens
before
66
When fracture site completely bridged by woven bone
bony union
67
Bony callous progressively remodelled
mature lamellar bone
68
Process takes ~ 6-12 wks, depending on (2)
severity & location
69
Synovial—characterized by
extensive movement
70
synovial joint is also known as
diarthroses
71
synovial joint/diarthroses are surrounded by
connective tissue capsule
72
connective tissue capsule
joint capsule
73
Lined by thin, discontinuous layer of cells,
synovium
74
synovium secretes
synovial fluid
75
synovial fluid bathes the
articular surface
76
No basement membrane, so not a
true epithelium
77
synovial "epithelia" is made of up to 4 cell layers of
synovial cells of mesenchymal origin
78
Two types of cells
A & B
79
Type A (2)
synoviocytes
| resemble Mφ
80
Type B
resemble fibroblasts
81
Nonsynovial
limited movement; joined by dense connective tissue, lacks articular surface
82
Syndesmosis
dense fibrous tissue between bones In skull, progressively replaced by bone to become synostosis(aka “sutures”)
83
Synchondrosis
(1’ cartilage joint) contains single layer of hyaline cartilage
84
what unites first rib with sternum?
synchondrosis
| only one in human adult
85
Symphysis
(2’cartilage joint), contains two hyaline cartilage surfaces connected by fibrocartilage plate
86
Intervertebral joints are a special type of
symphysis
87
Contain intervertebral discs, evolutionarily derived from --- in chordates
notochord
88
Formed of concentric layers of
fibrocartilage
89
Forms annulus fibrosus around central core of viscous ground substance,
nucleus pulposus
90
Damage to annulus fibrosus causes nucleus pulposus to
herniate
91
Damage to annulus fibrosus causes nucleus pulposus to herniate, resulting in a
herniated disc
92
inflammationof joints
arthritis
93
Osteoarthritis (2)
progressive degeneration & loss of articular cartilage
94
Leads to eburnation, pitting, erosion resulting in (3)
pain, swelling, thickening of joint capsule
95
Osteophytes
production of irregular new bone at edges of articular surfaces; aka “bone spurs”
96
Limits range of
motion
97
Progressive build-up of osteophytes, osteoarthritis or trauma can lead to
ankylosis
98
ankylosis
bony fusion of joint with loss of mobility
99
Rheumatoid arthritis
local, autoimmune rxn in joints => body produces Ab’s that attack joints => pain, damage to articular cartilage; thickening, inflammation of synovial membrane
100
pannus
replacement of articular cartilage with fibrovascular tissue
101
Gout
deposit of urates & uric acid crystals in joints (especially fingers & toes)
102
gout is extremely painful, associated with consumption of large quantities of (2)
red wine, meat
103
gout is also caused by certain vegetables—(4)
asparagus, broccoli, cauliflower, Brussel’s sprouts
104
All represent new plant growth, high in (2)
protein & [N]
105
Some diuretics used to treat hypertension can also cause
gout
106
Rickets
bone matrix doesn’t calcify normally in children during growth
107
rickets results in
soft, deformed bones
108
rickets can be
permanent
109
rickets are due to insufficient dietary (2)
Ca or Vit D
110
In adults, insufficient Ca & Vit D can lead to
osteomalacia
111
osteomalacia
failure of mineralization, softening of bone
112
Osteoporosis
loss of bone mass
113
Resorption by osteoclasts exceeds deposition by
osteoblasts
114
Common problem in post-menopausal women, possibly due to
decreased estrogen levels
115
Tx with oral Ca supplementation & Vit D for increased
Ca absorption
chondroitin, glucosamine, gelatin also helpful
116
Newer osteoporosis meds, e.g., Fosamax, bind phosphates in GI tract, minimize
absorption
117
Possible side effects include
mandibular necrosis
118
--- necessary for synthesis of collagen
Vit C
119
Vit C deficiency results in
scurvy
120
scurvy
bone matrix not calcified
121
Can also lead to weakening of collagen in
ligaments
122
especially periodontal ligament, resulting in
loose teeth
123
Breakdown of scars/ old wounds, which (2)
break open & bleed
124
Tx with fruits & vegetables high in
Vit C
e.g., citrus fruits—oranges, lemons, limes; also guavas
