chapter 6- skeletal system Flashcards
1
Q
what are the four components of the skeletal system?
A
bones, cartilage, tendons, and ligaments
2
Q
what are the functions of the skeletal system ?
A
framework for the body, protection, allows movement, stores minerals in the bone, stores adipose in bone cavity, red bone marrow, and hematopoesis
3
Q
what is hematopoiesis?
A
the creation of blood cells
4
Q
what do tendons attach to?
A
muscles and bones
5
Q
what do ligaments do?
A
hold bones together
6
Q
what are the three types of cartilage ?
A
hyaline
elastic
fibrocartilage
7
Q
hyaline cartilage
A
found on the ends of bones and in the nose
gives rise to the skeleton when developing
glassy appearance
collagen
8
Q
elastic cartilage
A
elastin
flexible
found in external ear and epiglottis
9
Q
fibrocartilage
A
collagen fibers
strong
found in pubic symphysis, knee meniscus, and intervertebral discs
maintains height
10
Q
what are the types of cartilage growth?
A
appositional and interstitial
11
Q
appositional growth
A
cartilage forming cells secrete new matrix against external face of existing cartilage
adds more to surface
12
Q
interstitial growth
A
chondrocytes divide and secrete new matrix
expand cartilage from within
13
Q
what is the bone matrix?
A
“reinforced concrete”
14
Q
what does collagen do?
A
adds flexible strength
lose=brittle
15
Q
what does minerals do for bones?
A
(hydroxyapetite)
weight bearing strength
lose= bend
16
Q
what are the bone cells?
A
osteoblasts, osteocytes, osteoclasts
17
Q
what are the ossification bone types?
A
woven and lamellar
18
Q
final bone types:
A
compact and spongey
19
Q
osetoblasts
A
builds matrix, turns chondrocytes into bone
osteogenesis/ ossification
lay down new bone on the surface (appositional)
arise from stem cells
20
Q
osteocytes
A
maintain matrix, 90-95% of bone cells
arise from osteoblasts, live up to 25 years
found in lacunae,
communicate via canalicoli
connects 1 cell to another, anchors, attaches, and communicates
21
Q
osteoclasts
A
breakdown matrix (reabsorption)
calcium in blood
arise from bone marrow
22
Q
when does ossification occur
A
as a fetus
when growing
when a fracture is repaired
23
Q
woven bone
A
formed first by osteoblasts, weak due to random placement of collagen, osteoclasts break down woven bone
24
Q
lamellar bone
A
formed by osteblasts to build stringer, more permanent bone
arranged in concentric sheets/layers=lamellae
parallel arrangement= strong
more consistent= more strength
25
spongey bone
appears porous with more space
consists of trabecular= interconnected roots
thin, found along mechanical stress lines
26
compact bone
more bone matrix
dense, solid outer layer
osteoblasts/ haversian system= unit
concentric rings of lamellae
shaft of bone, vascular
27
what are the types of bone?
long bone
flat bone
short and irregular bone
28
what is long bone made up of ?
compact bone with a medullary cavity in the center
29
diaphysis
the main shaft of the long bone
30
epiphysis
the ends of the long bones, mostly made out if spongey bone
covered in articular cartilage
31
epiphyseal plate
"growth plate"
between two parts
occurs on both ends
becomes the epiphyseal line when growth is complete
32
red bone marrow
gives rise to blood cells in the epiphyses
33
yellow bone marrow
adipose in the diaphysis
34
what are the layers of the long bone?
periosteum and the endosteum
35
periosteum
the outer surface
made of dense irregular tissue
36
endosteum
inner surface= bone
37
sharpeys fibers
perforating
attachment and strengthens area for ligaments/ tendons
38
flat bone
"spongey bone sandwich"
compact, spongey, compact
39
short and irregular bones
no diaphysis
small growth plates
40
types of fetal ossification
intramembraneous and endochondral
41
intramembraneous
starts with mesenchymal, embryonic connective tissue (fibrous) = flat (cranium)
emery at 8 weeks= 2 years old
42
endochondral
hyaline cartilage- long bone
43
what areas use endochondral fetal ossification ?
base of the skull, mandible area, clavicle epiphyses, rest of skeleton
embryo t 8 weeks in some areas
other areas start at 18-20 years old
44
intramembraneous ossification
begins at ossification centers, expands to form bone slowly.
centers have the oldest bone and the edges are the youngest
45
fontanels
soft spots, covered by membranes, bone fuse to cover, allows for brain growth
complete after aprox. 22 months
frontal is the largest
46
what is the process of intramembraneous ossification ?
1. osteoblast formation
2. spongey bone formation
3. compact bone formation
47
what happens during osteoblast formation?
step 1, mesenchymal cells (give rise to everything)
osteochondral progenitor cells (bone or cartilage cells), osteoblasts (lay down bone matrix) and become osteocytes
trabecular join together to form spongey bone
48
what happens during spongey bone formation?
step 2, osteoblasts present on trabecular surface, causing it to become larger and longer
trabecular join together to form spongey bone
49
what happens during compact bone formation?
red bone marrow forms as well as the periosteum.
osteoblasts from periosteum lay down bone matrix to form compact bone
creates spongey bone sandwich
50
what are the steps of endochondral ossification?
1. cartilage model formation
2. bone collar formation
3. primary ossification center
4. secondary ossification center
5. adult bone
51
what happens during cartilage model formation?
step 1 of endochondral ossification
mesenchymal cells, osteochondral progenitor cels, chondroblasts, chondrocytes, and hyaline cartilage model start to make bone
52
what happens during bone collar formation?
step 2 of endochondral ossification
osteoblasts, compact bone on cartilage model surface, and bone collar: grow from the inside out (hypertrophy)
form hydroxyapatite crystals (for strength), calcified cartilage, NO nutrition- matrix breaks down and forms lacunae (gets hollowed out)
53
what happens during primary ossification center?
step 3 of endochondral ossification
blood vessels grow into lenlarged lacunae, primary ossification center forms as osteoblasts and lay down bone on calcified cartilage surface
osteoblasts change calcified cartilage into diaphysis into spongey bone
cartilage model grows, bone collar thickens. osteoclasts remove diaphysis cent. medullary cavity
54
what happens in secondary ossification center?
step 4 of endochondral ossification
created in epiphyses, form in proximal epiphyses of femur, humerus, tibia (1 month prior to birth). last appears in medial epiphyses of clavicle (18-20)
continual cartilage, bone; when done growing the epiphyseal plate becomes the epiphyseal line.
55
what happens when creating adult bone?
step 5 of endochondral ossification
mature body (spongey and compact bone is fully developed), epiphyseal plate becomes epiphyseal line
56
where do bones grow at?
the epiphyseal plate
57
what does the physical plate connect?
the diaphysis to the epiphysis
also called the metaphysis
58
what do long bones do in regards to the epiphyseal plate
lays down cartilage in the epiphyseal plate
59
how do bones grow?
expands on both ends
bone is added to diaphysis through calcification
epiphyseal ends are pushed out to grow longer
60
what is the rate of cartilage growth on the epiphyseal side of the plate equal to?
the rate of bone formation on diaphysial side of the plate
61
what happens when you reach normal adult size?
you stop growing
epyphyseal plate ossifies into the epiphyseal line
complete by age 12-25 y/o.
damage to plate may interfere with bone length
62
how often does remodeling occur?
constantly
63
what factors can affect bone growth?
genes
nutrition
vitamin d
vitamin c
hormones
64
how often is the entire skeleton replaced?
every 10 years
65
how do genes affect bone growth ?
determine final height
66
how does nutrition affect bone growth ?
malnutrition leads to stunted growth
67
how does vitamin d affect bone growth ?
needed for calcium absorption from intestines, synthesis is increased when exposed to sunlight
need to make or ingest it
lack leads to rickets in kids, and osteomalacia in adults (softening of bones from calcium depletion)
bowed knees and inflamed joints
68
how does vitamin c affect bone growth ?
need for osteoblasts to make collagen
deficiencies lead to growth retardation
scurvy- ulceration and hemorrhage, impaired wound healing and teeth fall out.
69
how do hormones affect bone growth ?
growth hormone from pituitary gland
gigantism- xs hormones
dwarfism- insufficient
thyroid hormones, reproductive hormones, females -18 males -25
70
remodeling throughout a lifetime involves what?
bone deposit, bone resorption, control
71
bone deposit
uses osteoblasts
bone injuries, need extra bone strength
72
bone resorption
uses osteoclasts, breakdown matrix where there is less stress
73
control in remodeling
uses negative feedback and hormones (blood calcium levels)
calcitonin- C cells of thyroid (osteoblasts activate)
PTH - osteoclasts activate, release into bloodstream
74
what is wolff's law?
bones remodel in response to force/stress placed upon it
75
hormonal stress with remodeling
determines whether and when remodeling will occur in response to changing blood calcium levels
76
mechanical stress with remodeling
determines where remodeling occurs
wolff's law
77
mechanism of fracture
trauma, pathologic, and periprosthetic
78
bone fracture classifications
mechanism
soft tissue damage
displaced/not
fracture pattern
# of and arrangement of bone fragments
age
79
soft tissue damage with bone fracture classifications
closed vs open (compound)
80
displaced vs not with fractures
linear (parallel to bone length)
spiral (twisting)
avulsion (bone fragment)
stress (hairline, from overuse)
compression (weak= collapses)
81
of fragments and arrangement of bone fragments
incomplete (part of the bone)
82
age specific with bone fractures
greenstick fracture- 1 side breaks and 1 side bends
epiphyseal- uneven growth
83
what are the 4 steps to repair bone damage?
1. hematoma formation
2. fibrocartilagenous callus formation
3. bony callus formation
4. remodeling
84
hematoma formation in bone repair
step 1 , takes about 4 days
mass of clotted blood at fracture site, bone cells die from lack of nutrition, tissue becomes inflamed
85
fibrocartilagenous callus formation in bone repair
step 2
soft granulation tissue, capillaries and phagocytes into area, spongey bone forms, callus splints bone
86
bony callus formation in bone repair
step 3, takes 3-4 weeks to 2-3 months
osteoblasts and osteoclasts multiply, callus and spongey bone
87
remodeling in bone repair
step 4, takes several months
extra material outside and inside of bone
88
what is woven bone viewed as?
a quick fix
89
how are fractures treated
by reduction (realigning the fracture ends)
90
closed fracture
ends together by manual manipulation
91
open fracture
surgery performed, ends held together by pins/plates
open reduction internal fixation (ORIF)
external fixation- used when ORIF is too dangerous- requires 2nd surgery once swelling has improved
might needs pins to secure
92
paget's disease
high ratio of woven bone to compact
xs abnormal bone reabsorption and formation
bone becomes soft and weak
decreases osteoclast activity
osteoblasts form irregular bone thickness
93
what and who does paget's disease affect?
men and women over 40
affects spine, pelvis, femur, and skull
94
osteoporosis
weakened and porous bone, deformity leads to fractures
2.5 x more likely in women, worsens with age
bone mineral density decreases at 40
95
causes of osteoporosis
decreased reproductive hormone levels, inadequate diet, decreased calcium intake, sedentary, disuse from injury, oophorectomy, cigarette smoking, proton pump inhibitors for acid reflux use x5 years
96
what does osteoporosis affect?
decreases height and kyphosis
affects vertebral area, forearm, and pelvis
97
how is osteoporosis diagnosed ?
DEXA scan- dual energy x-ray absorptiometry
98
how do you prevent osteoporosis?
1200 mg calcium daily (50+), diary in diet, vitamin D 800 iu daily, avoid high phosphorus foods, avoid xs alcohol and caffeine, weight bearing exercise 30 min a day 3 times a week
99
treatment for osteoporosis
bisphosphonates (weekly or monthly) as osteoclast inhibitors
estrogen like meds
antibodies activate bone breakdown
calcitonin replacement
zoledronic acid yearly shot
