Chapter 7 Flashcards
1
Q
general components of the skeletal system (4)
A
bones, cartilage, ligaments, other connective tissues
2
Q
ligaments vs. tendons
A
ligaments - connect bone to bone
tendons - connect muscle to bone
3
Q
what is bone?
A
primary organs of the skeletal system
4
Q
function of bone?
A
forms the rigid framework of the body and perform other functions
5
Q
two types of bone
A
compact bone and spongy bone
6
Q
compact bone
A
dense, cortical bone; 80% of bone mass
7
Q
spongy bone
A
cancellous, trabecular bone; internal to compact bone; porous appearance; makes 20% of bone mass
8
Q
cartilage
A
semirigid connective tissue that is more flexible than bone
9
Q
two types of cartilage associated with the skeletal system?
A
hyaline cartilage and fibrocartilage
10
Q
costal cartilage
A
hyaline cartilage that attaches ribs to sternum
11
Q
articular cartilage
A
hyaline cartilage covering the end of the bone
12
Q
epiphyseal plates
A
hyaline cartilage within growth plates
13
Q
fibrocartilage
A
weight bearing cartilage that withstands compression
14
Q
what does fibrocartilage form?
A
intervertebral discs, pubic symphysis, menisci
15
Q
menisci
A
cartilage pads of knee joints
16
Q
pubic symphysis
A
cartilage between pelvic bones
17
Q
general functions of bone (4)
A
support and protection, levers for movement, hematopoiesis, storage of mineral/energy reserves
18
Q
how do bones provide support and protection?
A
structural support; serves as framework for the whole body
bones also protect delicate tissues and organs from injury and trauma
19
Q
how do bones serve as levers for movement?
A
skeletal muscle attached to bone contract and exert a pull on the skeleton, which then functions as a system of levers
20
Q
what is hematopoiesis?
A
process of blood cell production
21
Q
where does hematopoiesis occur?
A
within the red bone marrow connective tissue
22
Q
what does the red bone marrow connective tissue contain that helps support blood cell synthesis?
A
stem cells that form blood cells and platelets
23
Q
what minerals are stored within/released from bone?
A
calcium and phosphate
24
Q
what is calcium?
A
essential mineral for body functions such as muscle contraction, blood clotting, and neurotransmitter release from nerve cells
25
what is phosphate?
structural component of ATP, other nucleotides, and phospholipids
26
long bones
length > width
27
examples of long bones
fingers/toes, femur, tibia, fibula
28
short bones
length = width
29
examples of short bones
carpals/tarsals, sesamoid bones (sesame seed-shaped bones along tendons of muscles)
30
flat bones
flat, thin slices that may have slight curve
31
examples of flat bones
roof of skull, scapulae, sternum, ribs
32
irregular bones
elaborate, complex shaped bones
33
examples of irregular bones
vertebrae/hip bones, ethmoid, sphenoid, maxilla
34
long bone regions (7)
diaphysis
medullary cavity
epiphysis (proximal/distal)
metaphysis
epiphysial plate/line
periosteum
endosteum
35
diaphysis
shaft of the long bone
36
medullary cavity
hollow space within the diaphysis
37
epiphysis
end(s) of the long bone
38
metaphysis
between diaphysis and epiphysis
39
epiphyseal plate
hyaline cartilage providing for lengthwise growth of bone
40
periosteum
bone covering; covers outer surface of bone except for articulated cartilage
41
endosteum
bone lining; thin layer of connective tissue containing osteoprogenitor cells, osteoblasts, and osteoclasts
42
what is the diaphysis composed of?
mostly compact bone, however a thin layer of spongy bone extends inward
43
what does the medullary cavity contain?
bone marrow
44
proximal vs. distal epiphysis
proximal - the end closest to the trunk
distal - the end farthest from the trunk
45
what is the epiphysis composed of?
thinner compact bone; more abundant in spongy bone and covered with articular cartilage
46
what function does the metaphysis provide?
transferring forces between the diaphysis and epiphysis
47
where is the epiphyseal plate located?
within the *meta*physis
48
what does the epiphyseal plate become in adults?
epiphyseal line
(how? cartilage turns into bone, and can no longer grow in length)
49
what is the outer layer of the periosteum composed of?
dense irregular connective tissue
(blood vessels and nerves too, and is the site of tendon/ligament attachment)
50
what is the inner layer of the periosteum composed of?
(aka cellular layer) osteoprogenitor cells, osteoblasts, and osteoclasts
51
what growth type is the periosteum responsible for?
bone width
52
how is the periosteum anchored to bone?
by perforating fibers which run perpendicular to diaphysis
53
what does the endosteum cover?
all internal surfaces within the medullary cavity
54
anatomy of other bone classes? (not as complex as bone)
external surfaces are compact bone covered by periosteum; no medullary cavity
55
what is the interior of other bone classes aside from long bone?
spongy bone
(within flat bones? diploe)
56
is spongy bone vascular or avascular?
*highly* vascular; vessels enter from periosteum
57
small openings/holes in bones
nutrient foramens
58
function of nutrient foramens?
allows for arteries and veins to pass through, including nerves
59
bone marrow
softer connective tissue
60
function of *red* bone marrow
forms red blood cells
61
where can you find red bone marrow in *children?*
in medullary cavity + spongy bone of long bones
62
where can you find red bone marrow in *adults*?
select areas; skull, vertebrae, ribs, sternum, coxal bones, proximal epiphyses of humerus and femur
63
how is yellow bone marrow formed?
red bone marrow degenerates over life span; no longer functions in blood cell production
64
what is a characteristic of yellow bone marrow?
yellow bone marrow is fatty (composed of adipose)
65
osteoid
semisolid organic form of bone matrix
66
osteoprogenitor cells
stem cells derived from mesenchyme; divides and becomes “committed” cells, in which then they mature into osteoblasts
67
location of osteoprogenitor cells?
found in periosteum and endosteum
68
osteoblasts
synthesize + create osteoid that will eventually calcify; builds bone
69
what happens when osteoblasts get trapped in the matrix?
they become osteocytes
70
osteocytes
mature bone cells that maintain the bone matrix and detect bone stress
71
what happens if bone stress is detected?
osteoblasts are signaled, leading to formation of new bone
72
osteoclasts
large, multinuclear, phagocytotic cells that phagocytose bone; breaks down/resorbs bone
73
organic components of bone matrix?
osteoid - contains collagen proteins and semisolid ground substance of *proteoglycans* and *glycoproteins*
74
characteristics of organic components of the bone matrix
resistant to stretch - tensile strength; allows for some flexibility
75
inorganic components of bone matrix?
salt crystals made of calcium phosphate
76
what do salt crystals form when they interact with calcium hydroxide?
hydroxyapatite crystal
77
when crystals deposit around collagen fibers, what will it do to the matrix?
harden the matrix; make it more rigid
78
bone formation
occurs when osteoblasts secrete osteoid
79
what occurs during bone formation?
- osteoblasts secrete osteoid
- calcification occurs
- hydroxyapatite crystals are deposited into bone matrix
80
what initiates calcification in bone formation?
when calcium and phosphate ion concentration is high, thus it “leaks” out of the solution
81
requirements of bone formation
vitamin D, vitamin C, calcium, phosphate
82
vitamin D in bone formation
better calcium absorption
83
vitamin C in bone formation
collagen production
84
calcium and phosphate in bone formation
calcification
85
bone resorption
osteoclasts release substances that destroy bone matrix; proteolyotic enzymes released from lysosomes
86
osteon
small cyndrical structure; basic structural and functional unit of mature compact bone
87
osteon will always be parallel to what?
to the diaphysis
88
components of osteon
central canal
concentric lamellae
osteocytes
canaliculi
89
central canal
has blood vessels and nerves
90
concentric lamellae
surrounding rings of central canal; orientation of collagen fibers, provides strength and resilience
91
osteocytes
mature bone cells found in lacunae; maintain the bone matrix
92
canaliculi
interconnecting channels between lacuna; connect lacuna to central canal
93
trabeculae
lattice pattern of bone; bone marrow is in spaces, helps bone resist stress
94
hyaline cartilage histology
cells within matrix of protein fibers; gel-like ground substance of proteoglycans
95
characteristics of hyaline cartilage
- resilient; flexible
- avascular
- high water %
- no nerves
- compressible; shock-absorbing
96
chondroblasts
produce cartilage matrix
97
what happens when chondroblasts get trapped in the matrix?
they mature into chondrocytes
98
two methods of cartilage growth
interstitial and appositional
99
interstitial cartilage growth
increase in *length* that occurs *within* internal regions of cartilage
100
1st step of interstitial growth
chondrocytes housed within lacunae are stimulated to undergo mitosis
101
2nd step of interstitial growth
(after cell division) two cells occupy single lacuna; now called **chondroblasts**
102
3rd step of interstitial growth
chondroblasts synthesize + secrete cartilage matrix, making them push apart - each cell resides in their own lacuna; now called **chondrocytes**
103
4th (final) step of interstitial growth
cartilage continues to grow within internal regions as *chondrocytes produce more matrix*
104
appositional growth
increase in *width* along cartilage’s *outside edge*
105
1st step of appositional growth
**stem cells** within **perichondrium** begin to divide (perichondrium contains *mesenchymal* cells too)
106
2nd step of appositional growth
new undifferentiated stem cells + committed cells (chondroblasts) form; these chondroblasts are located in the outside of old cartilage and produce/secrete cartilage matrix
107
3rd (final) step of appositional growth
chondroblasts push apart and turn into chondrocytes (result of matrix formation), and cartilage continues to grow on periphery as more matrix is produced
108
ossification
(a.k.a. osteogenesis) formation and development of bone connective tissue
109
where does ossification begin?
in the embryo; continues throughout childhood-adolescence
110
what happens to the skeleton during the 8-12wks of embryonic development?
skeleton begins forming thickened condensations of mesenchyme (intramembranous) or hyaline cartilage model of bone (endochondral)
111
intramembranous ossification
bone growth **within a membrane**
112
what does intramembranous ossification produce?
flat bones of skull, some of the facial bones, central part of clavicle
113
when does intramembranous ossification begin?
when mesenchyme becomes thickened/condensed w/ dense supply of blood capillaries
114
step 1/4 of intramembranous ossification
ossification centers form within thickened regions of mesenchyme beginning @ 8th week of development
115
step 1/4 of intramembranous ossification
- ossification centers form within thickened regions of mesenchyme beginning @ **8th week of development**
- some thickened/condensed mesenchyme **divide**
- committed cells turn into **osteoprogenitor cells**; some become **osteoblasts** and **secrete osteoid**
- **ossification centers develop within thickened mesenchyme** as osteoblast # increases
116
step 2/4 of intramembranous ossification
- **osteoid undergoes calcification**
- calcium salts are deposited onto osteoid then **crystalize**
- calcification **entraps osteoblasts within lacunae** in matrix; trapped cells become **osteocytes**
117
step 3/4 of intramembranous ossification
- **woven bone + surrounding periosteum form**
- woven bone = immature/disorganized bone connective tissue (primary bone)
- later replaced by **lamellar bone** (secondary bone)
- mesenchymal cells grow and develop to produce additional osteoblasts; new blood vessels branch from here
- trabeculae is calcified and becomes spongy bone
118
step 4/4 of intramembranous ossification
- **lamellar bone replaces woven bone; compact bone and spongy bone are formed**
- lamellar bone replaces trabeculae of woven bone
- external: spaces between trabeculae are filled; bone becomes compact
- internal: spaces between trabeculae are modified; bone becomes spongy
119
endochondral ossification
begins with hyaline cartilage model + produces most bones of the skeleton
120
what does endochondral ossification produce?
upper/lower limbs, pelvis, vertebrae, ends of clavicle; long bone development
121
step 1/6 of endochondral ossification
- **fetal hyaline cartilage model develops** during 8-12ws development
- chondroblasts secrete cartilage, forming hyaline cartilage
- chondrocytes are trapped within lacunae, perichondrium surrounds cartilage
