skeletal system Flashcards
1
Q
Skeletal Cartilages
A
Contain no blood vessels or nerves
Dense connective tissue girdle of perichondrium contains blood vessels for nutrient delivery to cartilage
2
Q
Hyaline cartilages
A
imperceptable, nose joints, chondroblasts, supports, reinforces, resists repetetive stress
3
Q
Fibrocartilages
A
thick collagen fibers, tensile strength and shock absorber, discs
4
Q
elastic cartilage
A
more elastic fibers, big lacunae
5
Q
articular surface
A
where things go together and touch
6
Q
growth of cartilage appositional
A
Cells secrete matrix against the external face of existing cartilage
7
Q
growth of cartilage interstitial
A
Chondrocytes divide and secrete new matrix, expanding cartilage from within
8
Q
growth of cartilage calcification occurs during
A
normal bone growth, old age
9
Q
two main groups of bones (by location)
A
Axial skeleton (brown) Appendicular skeleton (yellow)
10
Q
Axial skeleton (brown)
A
straight down axis. skull, vertebrae, ribs
11
Q
Appendicular skeleton (yellow
A
appendages. arms, legs
12
Q
Long bones
A
Longer than they are wide
13
Q
Short bones
A
Cube-shaped bones (in wrist and ankle) Sesamoid bones (within tendons, e.g., patella)
14
Q
flat bones
A
Thin, flat, slightly curved
skull sternum
15
Q
irregular bones
A
complicated bones
vertebrae
16
Q
functions of bones
A
support (For the body and soft organs)
protection (For brain, spinal cord, and vital organs)
movement (Levers for muscle action)
storage (calcium, phorphorous, growth factors, triglyceride energy)
blood cell formation in marrow cavities
17
Q
bone Bulges, depressions, and holes serve as
A
Sites of attachment for muscles, ligaments, and tendons
Joint surfaces
Conduits for blood vessels and nerves
18
Q
Tuberosity
A
rounded projection
19
Q
Crest
A
narrow, prominent ridge
20
Q
Trochanter
A
large, blunt, irregular surface
21
Q
Line
A
narrow ridge of bone
22
Q
Tubercle
A
small rounded projection
23
Q
Epicondyle
A
raised area above a condyle
24
Q
Spine
A
sharp, slender projection
25
Process
any bony prominence
26
projections that help form joints
head
facet
condyle
ramus
27
head
Bony expansion carried on a narrow neck
28
facet
Smooth, nearly flat articular surface
29
condyle
Rounded articular projection
30
ramus
armlike bar
31
meatus
canal like passageway
32
sinus
Cavity within a bone
33
fossa
Shallow, basinlike depression
34
groove, furrow
narrow depression
35
fissure
Narrow, slitlike opening
36
foramen
Round or oval opening through a bone
37
Compact bone
Dense outer layer
38
spongy bone
Honeycomb of trabeculae
39
structure of long bone
Diaphysis
| Epiphyses
40
Diaphysis
shaft)
Compact bone collar surrounds medullary (marrow) cavity
Medullary cavity in adults contains fat (yellow marrow)
41
Epiphyses
```
Expanded ends
Spongy bone interior
Epiphyseal line (remnant of growth plate)
Articular (hyaline) cartilage on joint surfaces
```
42
Periosteum
Outer fibrous layer
Inner osteogenic layer
Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina
Secured to underlying bone by Sharpey’s fibers
43
what cells are in inner osteogenic layer
Osteoblasts (bone-forming cells)
Osteoclasts (bone-destroying cells)
Osteogenic cells (stem cells)
44
endosteum
Delicate membrane on internal surfaces of bone
| Also contains osteoblasts and osteoclasts
45
Structure of Short, Irregular, and Flat Bones
```
no epiphysis no diaphysis
Periosteum-covered compact bone on the outside
Endosteum-covered spongy bone within
Spongy bone called diploë in flat bones
Bone marrow between the trabeculae
```
46
Red marrow cavities of adults
Trabecular cavities of the heads of the femur and humerus
| Trabecular cavities of the diploë of flat bones
47
Red marrow of newborn infants
Medullary cavities and all spaces in spongy bone
48
Osteogenic (osteoprogenitor) cells
Stem cells in periosteum and endosteum that give rise to osteoblasts
49
Osteoblasts
Bone-forming cells
50
Osteocytes
```
mature bone cells
in senescence (not dividing) until break bone
```
51
Osteoclasts
Cells that break down (resorb) bone matrix
| Involved in bone repair
52
osteon
```
haverisian system
contain lamellae (made of collagen fibers)
central canal (blood vessels, nerves)
perforating canals
lacunae
canaliculi
```
53
Perforating (Volkmann’s) canals
At right angles to the central canal
| Connects blood vessels and nerves of the periosteum and central canal
54
lacunae
small cavities that contain osteocytes
55
canaliculi
hairlike canals that connect lacunae to each other and the central canal
56
spongy bone contains
trabeculae
Align along lines of stress
No osteons
Contain irregularly arranged lamellae, osteocytes, and canaliculi
Capillaries in endosteum supply nutrients
57
Chemical Composition of Bone: Organic
Osteogenic cells, osteoblasts, osteocytes, osteoclasts
| osteoid
58
Osteoid
organic bone matrix secreted by osteoblasts
Ground substance (proteoglycans, glycoproteins)
Collagen fibers
59
Chemical Composition of Bone: Inorganic
Hydroxyapatites (mineral salts)
65% of bone by mass
Mainly calcium phosphate crystals
Responsible for hardness and resistance to compression
60
Osteogenesis (ossification)
bone tissue formation
61
bone development stages
Bone formation—begins in the 2nd month of development
Postnatal bone growth—until early adulthood
Bone remodeling and repair—lifelong
62
two types of ossification
Intramembranous ossification
| Endochondral ossification
63
Intramembranous ossification
Membrane bone develops from fibrous membrane
| Forms most flat bones (cranial bones)
64
Endochondral ossification
Cartilage (endochondral) bone forms by replacing hyaline cartilage
Requires breakdown of hyaline cartilage prior to ossification
Forms most of the rest of the skeleton
65
Intramembranous ossification steps
Ossification centers appear in the fibrous connective tissue membrane.
Bone matrix (osteoid) is secreted within the fibrous membrane and calcifies
Woven bone and periosteum form
Lamellar bone replaces woven bone, just deep to the periosteum. Red marrow appears.
66
Endochondral ossification steps
Bone collar forms around hyaline cartilage model
Cartilage in the center of the diaphysis calcifies and then develops cavities (medullar cavity)
The periosteal bud inavades the internal cavities and spongy bone begins to form (blood vessels go into medullar cavity in order for spongy bone to form)
The diaphysis elongates and a medullary cavity (thicker) forms as ossification continues. Secondary ossification centers appear in the epiphyses in preparation for stage 5.
The epiphyses ossify. When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages.
67
Postnatal Bone Growth interstitial
length of long bones
68
Postnatal Bone Growth appositional
thickness and remodeling of all bones by osteoblasts and osteoclasts on bone surfaces
69
for growth in long bones (interstitial ) Epiphyseal plate cartilage organizes into four important functional zones
Proliferation (growth, top epi plate lengthing, cells dividing) (grows toward)
Hypertrophic (big lacunae9
Calcification (break down lacunae)
Ossification (osteogenic) /bone)
70
Growth hormone stimulates
epiphyseal plate activity
71
Testosterone and estrogens (at puberty)
Promote adolescent growth spurts
| End growth by inducing epiphyseal plate closure
72
Bone Deposit
Occurs where bone is injured or added strength is needed
| Requires a diet rich in protein; vitamins C, D, and A; calcium; phosphorus; magnesium; and manganese
73
Sites of new matrix deposit are revealed by
Osteoid seam
| calcification front
74
osteoid seam
Unmineralized band of matrix
| Calcification front
75
calcification front
The abrupt transition zone between the osteoid seam and the older mineralized bone
76
Bone Resorption
Osteoclasts secrete
(Lysosomal enzymes (digest organic matrix)
Acids (convert calcium salts into soluble forms)
Dissolved matrix is transcytosed across osteoclast, enters interstitial fluid and then blood
77
Bone Remodeling
Resorption (removal) and deposit occurring together
| performed by osteoclasts and osteoblasts
78
Bone Remodeling occurs at
surface of periosteum and endosteum
79
does remodeling happen equally throughout skeleton
no, Areas of high stress remodeled more frequently to prevent those areas from becoming too brittle.
80
What controls continual remodeling of bone?
Hormonal mechanisms that maintain calcium homeostasis in the blood
Mechanical and gravitational forces sensed by osteocytes
(communicate to stimulate remodeling)
81
removal of osteocytes causes loss of
remodeling activities
82
Calcium is necessary for
```
Transmission of nerve impulses
Muscle contraction
Blood coagulation
Secretion by glands and nerve cells
Cell division
```
83
Hormonal Control of Blood Ca2+ flow chart
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Blood Ca2+ levels drop
Parathyroid glands increase release PTH
PTH stimulates osteoclasts to degrade bone matrix and release Ca2+
Blood Ca2+ levels increase
Parathyroid glands decrease PTH
```
84
wolffs law
A bone grows or remodels in response to forces or demands placed upon it
85
what fractures most common
extremities
86
most common in what man and women ages
in men up to 45 years of age
| in women over 45 years of age
87
before 75 years what fractures are most common
wrist
88
after 75 years what fractures are most common
hip
89
Bone fractures may be classified by four “either/or” classifications:
Position of bone ends after fracture
Completeness of the break
Orientation of the break to the long axis of the bone
Whether or not the bone ends penetrate the skin
90
Position of bone ends after fracture
Nondisplaced—ends retain normal position
| Displaced—ends out of normal alignment
91
Completeness of the break
Complete—broken all the way through
| Incomplete—not broken all the way through
92
Orientation of the break to the long axis of the bone
Linear—parallel to long axis of the bone
Transverse—perpendicular to long axis of the bone
Spiral or Oblique – on an oblique angle
93
Whether or not the bone ends penetrate the skin:
Compound (open)—bone ends penetrate the skin
| Simple (closed)—bone ends do not penetrate the skin
94
All fractures can be described in terms of
Location
External appearance
Nature of the break
95
Comminuted fracture
Three or more bone pieces - high energy trauma
| can require serious hardware to repair
96
Compression (crush) fractures
Fracture in spongy bone: result of compression (osteoporosis)
most common vertebrae
97
spiral or oblique fracture
Caused by violence transmitted through limb from a distance (twisting movements)
98
epiphyseal fracture
fracture at growth plate
99
depressed fracture
make a depression (shot in head, hammer to head)
100
Greenstick
Occurs in children: bones soft and bend without fracturing completely
101
Transverse fracture
Usually caused by directly applied force to fracture site
| perpendicular to disaphysis
102
Functions of the X-ray
Localises fracture and number of fragments
Indicates degree of displacement
Evidence of pre-existing disease in bone
Foreign bodies or air in tissues
May show other fractures
MRI, CT or ultrasound to reveal soft tissue damage
103
how to handle fracturea
reduction
maipulation
traction
104
open reduction
– Allows very accurate reduction
risk of infection
Usually when internal fixation is Needed
105
Manipulation
closed reduction
usually with anesthesia
setting bone
106
traction
Fractures or dislocation requiring slow pulling resistance.
107
Closed Reduction
a procedure to set (reduce) a broken bone without surgery
108
holding reduction external fixation
4-12 weeks, used for fractures too unstable for cast, pins and frames
109
Internal fixation
Pins, nails, compression plates, screws, intramedullary rods
110
frame fixation
Allows correction of deformities by moving the pins in relation to the frame
111
Stages in the Healing of a Bone Fracture
Hematoma forms
Fibrocartilaginous callus forms
Bony callus formation
Bone remodeling
112
Hematoma forms
Torn blood vessels hemorrhage
Clot (hematoma) forms
INFLAMMATION - Site becomes swollen, painful, and inflamed
– lasts 6-8 hours after injury
113
Fibrocartilaginous callus forms
Phagocytic cells clear debris
Osteoblasts begin forming spongy bone within 1 week
Fibroblasts secrete collagen fibers to connect bone ends
Mass of repair tissue now called fibrocartilaginous callus
lasts about 3 weeks
114
Bony callus formation
New trabeculae form a bony (hard) callus
| Bony callus formation continues until firm union is formed in ~2 months
115
Bone remodeling
In response to mechanical stressors over several months
| Final structure resembles original
116
Osteoporosis
Loss of bone mass—bone resorption outpaces deposit
Spongy bone of spine and neck of femur become most susceptible to fracture
Risk factors
117
Osteoporosis risk factors
Lack of estrogen, calcium or vitamin D; petite body form; immobility; low levels of TSH; diabetes mellitus
118
Osteoporosis: Treatment and Prevention
Calcium, vitamin D, and fluoride supplements
increase Weight-bearing exercise throughout life
Hormone (estrogen) replacement therapy (HRT) slows bone loss
Some drugs (Fosamax, SERMs, statins) increase bone mineral density
