Bone Flashcards
(119 cards)
1
Q
includes the bones, joints, and their associated supporting tissues
A
skeletal system
2
Q
What are the main organs of this system?
A
bone
3
Q
What is bone composed of?
A
- dense regular and irregular collagenous connective tissue
* bone marrow
4
Q
What are the functions of the skeletal system?
A
- protection
- mineral storage and acid-base homeostasis
- blood cell formation
- fat storage
- movement
- support
5
Q
certain bones, including skull, sternum (breastbone), ribs, and pelvis, protect underlying organs;
A
protection
6
Q
bone is most important storehouse in body for calcium, phosphorus, and magnesium salts; these minerals, also present in blood as electrolytes, acids, and bases; critical for electrolyte and acid-base maintenance
A
mineral storage and acid-base homeostasis
7
Q
bones house red bone marrow; specialized connective tissue involved in formation of blood cells
A
blood cell formation
8
Q
bones also contain yellow bone marrow; contains fat cells, or adipocytes, that store triglycerides; fatty acids from breakdown of triglycerides can be used for fuel by cells
A
fat storage
9
Q
bones serve as sites for attachment for most skeletal muscles; when muscles contract, they pull on bones; generates movement at a joint
A
movement
10
Q
skeleton supports weight of body and provides its structural framework
A
support
11
Q
can be organized into 5 classes despite diversity of bone appearance
A
bone structure
12
Q
what are the five classifications of bone by shape?
A
- long bone
- short bones
- flat bones
- irregular bones
- sesamoid bones
13
Q
named for overall shape; not their actual size; longer than they are wide; include most bones in arms and legs
A
long bone
14
Q
also named for shape rather than size; roughly cube-shaped or about as long as they are wide; include bones of wrist or carpals and ankle or tarsals
A
short bones
15
Q
thin and broad bones; include ribs, pelvis, sternum (breastbone), and most bones in skull
A
flat bones
16
Q
include vertebrae and certain skull bones; do not fit into other classes because of irregular shapes
A
irregular bones
17
Q
specialized bones located within tendons; usually small, flat, and oval-shaped; give tendons a mechanical advantage, which gives muscles better leverage; patella (kneecap) is an example of this class of bones
A
sesamoid bones
18
Q
membrane composed of dense irregular collagenous connective tissue; forms a covering, rich with blood vessels and nerves; surrounds outer surface of long bones
A
periosteum
19
Q
made of collagen; anchors periosteum firmly to underlying bone surface by penetrating deep into bone matrix
A
Perforating fibers (Sharpey’s fibers)
20
Q
shaft of a long bone; each end is its epiphyses; epiphysis is covered with a thin layer of hyaline cartilage (articular cartilage) found within joints (articulations) between bones
A
diaphysis
21
Q
- contains either red or yellow bone marrow, depending on bone and age of individual
- hollow cavity within the diaphysis
A
marrow cavity
22
Q
one of two bone textures; hard, dense outer region that allows bone to resist linear compression and twisting forces among other stresses
A
compact bone
23
Q
second bone texture found inside cortical bone; honeycomb-like framework of bony struts; allows long bones to resist forces from many directions; provides a cavity for bone marrow
A
spongy bone (cancellous bone)
24
Q
the connective tissue membrane lining the internal surfaces of a bone
A
endosteum
25
* found separating both proximal and distal epiphyses from diaphysis
* a calcified remnant of the epiphyseal plate
epiphyseal line
26
*a structure composed of hyaline cartilage from which long bones grow in length (found in developing children)
epiphyseal plate
27
where do short, flat, irregular, and sesamoid bones get there blood supply from?
provided mostly by vessels in periosteum that penetrate bone
28
where do long bones get there blood supply from?
* a third of their blood supply from periosteum; mostly supplies compact bone
* Remaining two-thirds is supplied by one or two nutrient arteries
29
consists of loose connective tissue that supports islands of blood-forming hematopoietic cells
red bone marrow
30
found only in pelvis, proximal femur and humerus, vertebrae, ribs, sternum, clavicles, scapulae, and some bones of skull
red marrow in adults
31
composed of triglycerides, blood vessels, and adipocytes
yellow bone marrow
32
primary tissue found in bone; composed mostly of extracellular matrix with a small population of cells scattered throughout
bone or osseous tissue
33
consisting of minerals makes up about 65% of bones total weight
inorganic matrix
34
makes up remaining 35%; consists of collagen fibers and usual ECM components
organic matrix
35
made up predominantly of calcium salts; bone stores around 85% of total calcium ions in body as well as a large amount of phosphorus
inorganic matrix
36
known as osteoid; consists of protein fibers, proteoglycans, glycosaminoglycans, glycoproteins, and bone-specific proteins
organic matrix
37
predominant protein fiber; forms cross-links with one another; helps bone resist torsion (twisting) and tensile (pulling or stretching) forces
collagen
38
bind all of different components of osteoid and inorganic matrix together
glycoproteins in osteoid
39
create an osmotic gradient that draws water into osteoid; helps tissue resist compression
Glycosaminoglycans and proteoglycans
40
process where osteoblasts secrete organic matrix materials and assist in formation of inorganic matrix
bone deposition
41
flattened cells that differentiate into osteoblasts when stimulated by specific chemical signals
osteogenic cells
42
* bone-building cells that perform bone deposition
| * metabolically active bone cells found in periosteum and endosteum
osteoblasts
43
Osteoblasts eventually surround themselves with bone matrix in a small cavity known as
lacuna
44
a mature bone cell that monitors and maintains the surrounding bone matrix
osteocyte
45
responsible for bone resorption; process where cell secretes hydrogen ions and enzymes that break down bone matrix
osteoclasts
46
a bone-destroying cell that secretes chemicals to dissolve the organic and inorganic matrices if bone tissue
osteoclasts
47
compact bone, in cross section, resembles forest of tightly packed trees where each tree is a unit called
osteon, or a Haversian system
48
arranged in layered ring structures , each osteon contains
lamellae
49
endosteum-lined hole found in center of each osteon where blood vessels and nerves reside to supply bone
central-canal
50
small cavities found between lamellae; filled with extra cellular fluid
lacunae
51
Neighboring lacunae are connected to one another by a network of small passageways or canals in matrix
canaliculi
52
found filling the spaces between circular osteons and represent remnants of old osteons
interstitial lamellae
53
outer and inner layers of lamellae just inside periosteum and at boundary with spongy bone; add strength to bone
circumferential lamellae
54
originate from blood vessels in periosteum and travel at right angles (perpendicular) to central canals of neighboring osteons;serve to connect them with one another
perforating canals (volkmanns' canals)
55
Struts or ribs of bone are called
trabeculae
56
covered with endosteum and usually not arranged into osteons
trabeculae
57
composed of concentric lamellae between which lacunae are found containing osteocytes; communicate with each other through canaliculi
trabeculae
58
(“marble bone disease”) is defective osteoclasts; do not properly degrade bone; causes bone mass to increase and become weak and brittle
osteoporosis
59
predominately inherited, more severe form; openings of skull and marrow cavities fail to enlarge with growth; traps nerves causing blindness and deafness and decreases blood cell production; can be fatal; must be treated with drugs to stimulate osteoclasts and red marrow
infantile osteoporosis
60
also inherited; develops during adolescence or later; symptoms: bone pain, recurrent fractures, nerve trapping, joint pain; treated symptomatically only
adult osteoporosis
61
Since there are no central or perforating canals supplying blood to the trabeculae, how do trabeculae obtain their blood supply?
from vessels in bone marrow
62
Process of bone formation is called
ossification or osteogenesis
63
built on a model (starting material) made of a membrane of embryonic connective tissue
Bones formed by intramembranous ossification
64
built on a model of hyaline cartilage
Bones formed by endochondral ossification
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forms many flat bones, including bones of skull and clavicles, during fetal development
intramembranous ossification
66
formed within a mesenchymal membrane composed of embryonic connective tissue; richly supplied with blood and populated with mesenchymal cells
primary bone
67
Middle layer of spongy bone ossifies before outer compact bone layers; begins from region called
primary ossification center
68
calcium salts and other inorganic matrix components are deposited in trabeculae over a few days process called
calcification
69
osteoblasts get trapped in lacunae and become
osteocytes
70
An example of early incomplete ossification is?
fontanels (soft spots) in skulls of newborn babies
71
* Bone development for all bones below head except clavicles
* Begins in fetal stage of development for most bones; some bones (wrist and ankle) ossify much later
* Many bones complete ossification by age 7
*endochondral ossification
72
occurs from within a model of hyaline cartilage; serves as a scaffold for developing bone
endochondral ossification
73
hyaline cartilage model is composed of?
* chondrocytes
* collagen
* ECM
74
Hyaline cartilage model is composed of chondrocytes, collagen, and ECM all surrounded by a connective tissue membrane called __________ and immature cartilage cells called _________
perichondrium, chondroblasts
75
how do chondroblasts in the perichondrium differentiate?
first into osteogenic cells then osteoblasts and periosteum is formed
76
Bone begins to form where osteoblasts have built?
bone collar on external surface of bone
77
calcified cartilage is replaced with and the the medullary cavity is filled with
bone marrow
78
cartilage only persists in two places which include?
the epiphyseal plates and the articular surfaces
79
persists into adulthood while epiphyseal plates are eventually filled in, once bone is finished growing in length
articular cartilage
80
Long bones lengthen by a process called
longitudinal growth
81
where does bone growth take place?
at the epiphysis on the side closest to the diaphysis
82
composed of hyaline cartilage that did not ossify zones of cells, each with a distinctive appearance
epiphyseal plate
83
(found closest to epiphysis) contains cells that are not directly involved in bone growth but can be recruited for cell division if need arises
Zone of reserve cartilage
84
(next region) consists of actively dividing chondrocytes by endochondral ossification, contains five different lacunae
zone of proliferation
85
(next region closer to diaphysis) contains mature chondrocytes
Zone of hypertrophy and maturation
86
(second to last region) contains dead chondrocytes, some of which have been calcified
zone of calcification
87
(last region) consists of calcified chondrocytes and osteoblasts
zone of ossification
88
forcing cells ahead of them into next zones, moving toward diaphysis, chondrocytes divide in the zone of?
proliferation
89
what happens to Chondrocytes that reach zone of hypertrophy and maturation?
enlarge and stop dividing
90
what happens to chondrocytes that reach the zone of calcification?
their matrix calcifies
91
Longitudinal growth continues at epiphyseal plate as long as mitosis continues in zone of
proliferation
92
Bones not only grow in length, they also grow in width; process called
appositional growth
93
found in between periosteum and bone surface, lay down new bone
osteoblasts
94
Appositional growth does not result in immediate formation of osteons; instead, what is formed?
new circumferential lamellae are formed
95
One of main factors affecting bone growth is a group of chemicals called
hormones
96
secreted by anterior pituitary gland; enhances protein synthesis and cell division in nearly all tissues, including bone
growth hormone
97
* It increases rate of cell division of chondrocytes in epiphyseal plate
* It increases activity of the osteogenic cells, including their activity in zone of ossification
* It directly stimulates osteoblasts in periosteum; triggers appositional growth
Effects of growth hormone on both longitudinal and appositional growth
98
* Increases appositional growth causing bones in males to become thicker with more calcium salt deposition than in females
* Increases rate of mitosis in epiphyseal plate; leads to “growth spurts” in teenage years
* Accelerates closure of epiphyseal plate
Male sex hormone testosterone has a pronounced effect on bone growth:
99
* Increases rate of longitudinal bone growth and inhibits osteoclast activity
* When estrogen levels spike in teen years an accompanying “growth spurt” occurs in females
* Accelerates closure of epiphyseal plate at a much faster rate than testosterone; leads to average height differences between genders
Female sex hormone estrogen also plays a role in bone growth:
100
bone undergoes a continuous process of formation and loss called
bone remodeling
101
new bone is formed by
bone deposition
102
old bone is removed by
bone resorption
103
* Maintenance of calcium ion homeostasis
* Replacement of primary bone with secondary bone
* Bone repair
* Replacement of old brittle bone with newer bone
* Adaptation to tension and stress
Bone remodeling cycle
104
involves bone deposition and bone resorption
process of bone remodeling
105
carried out by osteoblasts, found in both the periosteum and endosteum, which make organic matrix and facilitate the formation of the inorganic matrix
bone deposition
106
heavier loads (compression) increase tissue deposited in that bone; tension and pressure also affect remodeling
Bone remodeling in response to tension and stress
107
squeezing or pressing together; occurs when bones are pressed between body’s weight and ground; stimulates bone deposition
compression
108
stretching force; bone deposition occurs in regions of bone exposed to tension
tension
109
continuous downward force; bone resorption is stimulated in regions of bone exposed to continuous pressure
pressure
110
Testosterone promotes bone deposition while estrogen inhibits osteoclast activity
hormones
111
As individual ages growth hormone and sex hormones decline; decreases protein synthesis in bone
age
112
when calcium ion level drops in blood it is detected by parathyroid cells
stimulus and receptor
113
parathyroid cells act as control center and secrete parathyroid hormone (PTH
control center and effector
114
As calcium ion levels return to normal in blood, change is detected by parathyroid cells and they reduce secretion of PTH, closing feedback loop
homeostasis and negative feedback
115
skin and tissue around fracture remain intact
simple fracture
116
skin and tissues around fracture are damaged
compound fracture
117
A hematoma fills in the gap between bone fragments. What is a hematoma?
mass of blood cells and proteins form in an injury due to ruptured blood vessels (blood clot)
118
Fibroblasts and chondroblasts infiltrate hematoma and form a soft callus. What is a soft callus?
mixture of hyaline cartilage and collagenous connective tissue
119
Osteoblasts build a bone callus. What is a bone callus?
(hard callus); collar of primary bone made by osteoblasts residing in periosteum
