Skeletal system Flashcards
(165 cards)
1
Q
What are the two main functions of the skeleton system?
A
protection and support
2
Q
What are the four complete functions of the skeleton system?
A
- protection/support
- aids in movement
- storage of minerals : Ca, P
- Hemopoiesis
3
Q
What does “hemo-“ mean?
A
blood
4
Q
What does “-poiesis” mean?
A
make more
5
Q
What type of tissue is bone?
A
supporting connective tissue
6
Q
What is another name for bone?
A
osseous
7
Q
What four categories make up the skeletal systems?
A
bones, cartilage, ligaments, and tendons
8
Q
Bones
A
rigidity; primary organs of the skeletal
9
Q
Cartilage
A
- flexibility
- cushioning
10
Q
Ligaments
A
connection of the skeletal components (bone to bone)
11
Q
Tendons
A
attachment of muscles to the skeleton (muscle to bone)
12
Q
What are the bone cells?
A
osteoprogenitors, osteoblasts, osteocytes, and osteoclasts
13
Q
Osteoprogenitors
A
stem cells that generate osteoblasts
14
Q
Osteoblasts
A
synthesize soft osteoid that later mineralizes while trapped in the bone matrix, osteoblasts differentiate (develop) into osteocytes
15
Q
Osteocytes
A
maintain ECM regulate other bone cells
16
Q
Osteoclasts
A
bone resorption = removal
17
Q
What does “gen-“ mean?
A
generate
18
Q
What does “-blasts” mean?
A
builder
19
Q
What does “-cytes” mean?
A
mature cells
20
Q
What does “-clasts” mean?
A
crusher
21
Q
What are osteoids mostly made up of?
A
collagen
22
Q
What is an identifying characteristic of osteocytes?
A
branches
23
Q
The bone matrix is split into what two categories?
A
organic and inorganic
24
Q
What are the organic structures in the bone matrix?
A
osteoids
25
What precent of osteoids are collagen?
90%
26
What is the function of osteoids in the bone matrix?
strength and some flexibility
27
What are the inorganic structures in the bone matrix?
minerals, primarily Ca3(PO4)4
28
What is the function of minerals in the bone matrix?
hardness
29
What is the result of collagen loss in the bone?
broken bones
30
What is the result of insufficient calcium?
soft bones
31
The bone matrix constantly goes under what processes?
bone formation and bone resorption
32
Bone formation is done by what cell?
osteoblasts
33
What are the two aspects of bone formation?
osteoids and mineralization
34
What does osteoids require?
vitamin C
35
What does mineralization require?
P, Ca, vitamin D
36
Bone resorption is done by what cell?
osteoclasts
37
What are the two aspects of bone resorption?
enzymes and HCL
38
What is the function of enzymes in bone resorption?
digest osteoids
39
What is the function of HCL in bone resorption?
dissolve Ca and P
40
What are the two types of bone tissue?
compact bone and spongy bone
41
What are the other names for compact bones?
dense and cortical
42
What are the units of compact bone?
osteons
43
What is another name for spongy bone?
trabecular
44
What are the units of spongy bone?
trabeculae
45
What features does spongy tissue provide?
- resistance but light weight
- spaces are filled with bone marrow
46
What do both compact and spongy bone contain?
vessels and nerves
47
What is the function of bone marrow?
hemopoiesis
48
What are the three sections of long bone?
Diaphysis, Epiphysis, and Metaphysis
49
Diaphysis
elongated shaft
50
Diaphysis function
leverage and major weight support
51
Diaphysis composition
- outer layer: compact bone
- inner layer: spongy bone
52
What cavity does the diaphysis cavity contain?
medullary cavity
53
Medullary cavity
houses red bone marrow
54
Epiphysis
knobby region at the ends of long bone
55
Epiphysis composition
- outer layer
- inner layer
- joint surface
56
Epiphysis outer layer is made of what?
compact bone
57
Epiphysis inner layer is made of what?
spongy bone
58
Epiphysis joint surface is covered by what?
articular cartilage
59
Metaphysis
region between diaphysis and epiphysis
60
The metaphysis section contains what plate?
epiphyseal plate
61
Epiphyseal plate
thin layer of hyaline cartilage that provides for lengthwise bone growth (till 25-26 years)
62
Epiphyseal line
remnant of epiphyseal plate in adults
63
What are the two kinds of bone linings?
periosteum and endosteum
64
Periosteum
cover the outer surface of bone
65
What are the two layers of periosteum?
fibrous and cellular
66
Fibrous layer of periosteum
protects; anchors vessels/nerves; attachment site for ligaments/tendons
67
Cellular layer of periosteum
includes osteoprogenitors, cells, osteoblasts, and osteoclasts
68
Endosteum
covers internal surfaces of the bone
69
Endosteum inclusions (what does it include?)
osteoprogenitor cells, osteoblasts, and osteoclasts
70
Bone are highly what?
vascularized
71
Vessels enter/exit through what?
nutrient foramen (small opening)
72
What usually accompanies blood vessels through the foramen?
sensory nerves
73
What kind of tissue is bone marrow?
soft connective tissue
74
Red bone marrow is what?
hematopoietic
75
Hematopoietic
forms all three blood cells
76
Red bone marrow contains what?
reticular connective tissue. immature blood cells, and adipocytes
77
Yellow bone marrow
product of red bone marrow conversion
78
Yellow bone marrow is rich in what?
adipocytes
79
Can yellow bone marrow be converted back into red bone marrow?
yes
80
What type of tissue is cartilage?
supporting connective tissue
81
What are the two substances in cartilage?
cells and ECM
82
What cells are found in cartilage?
chondroblasts and chondrocytes
83
Chondroblasts function
produce matrix
84
What is the ECM in cartilage made up of?
- ground substance rich in water (compressible)
- fibers (collagen and elastin)
85
What are the three features of cartilage?
- avascular
- no nerves
- perichondrium
86
Since cartilage is avascular, what does cartilage rely on to receive nutrients and oxygen?
slow diffusion through the matrix
87
Perichondrium
protective fibrous membrane layer
88
What does "peri-" mean?
around
89
What are the three types of cartilage?
hyaline, elastic, and fibrous
90
Hyaline cartilage
- thin collagen
- most abundant
91
Where can hyaline cartilage be found?
articular (joint), costal, nasal
92
Elastic cartilage
- most flexible (large amount of elastin)
93
Where can elastic cartilage be found?
external ear and epiglottis of the larnyx
94
Fibrous cartilage
thick collagen (most protect? and stretch resistant)
95
Where can fibrous cartilage be found?
knee/intervertebral discs
96
What are the two types of cartilage growth?
interstitial and appositional cartilage growth
97
Interstitial cartilage growth
"internal" expansion
98
Interstitial cartilage growth results in more what?
more matrix
99
Appositional cartilage growth
adding layers to the end
100
Appositional cartilage growth results in what?
more matrix and more cells
101
Where are layers added in appositional cartilage growth?
edge of the cartilage below the perichondrium
102
What kinds of cells occupy the perichondrium?
mesenchymal (stem) cells
103
Cartilage growth pattern: during early embryonic development
experiences interstitial and appositional cartilage growth
104
Cartilage growth pattern: what happens as cartilage matures?
it becomes semi-rigid, cannot expand and can only experience appositional growth
105
Cartilage growth pattern: fully matured cartilage
- does not grow
- has very limited ability to repair damages (avascular!!)
106
Ossification
bone formation
107
When does ossification begin?
begins in the embryo @ 8 weeks through adolescence
108
What are the two types of ossification?
intramembranous and endochondral ossification
109
How does intramembranous ossification initially start off as?
a membrane (layer) of mesenchyme (embryonic CT)
110
Intramembranous ossification is responsible for forming what?
flat skull bones and the clavicle
111
How does endochondral ossification initially start off as?
hyaline cartilage model
112
Endochondral ossification is responsible for forming what?
most bones
113
What are the stages of intramembranous ossification?
1. osteoblasts form ossification center
2. Cells trapped inside ossification center become osteocytes
3. woven bone is formed
4. woven bone becomes lamellar bone
114
Is woven bone weak or strong?
weak
115
Is lamellar bone weak or strong?
strong
116
What does "lamellar" mean?
layered
117
Endochondral ossification
1. start with the cartilage model
2. the cartilage breaks down, blood vessels begin to grow, and the periosteum
3. primary ossification center begins to form in the diaphysis
4. the secondary ossification center begins to form on the ends of the bone (epiphysis)
5. articular cartilage and the epiphyseal plate form
6. when the bones stop growing the epiphyseal plate becomes the epiphyseal line
118
Articular cartilage function
cushioning
119
What type of tissue is the epiphyseal plate made of?
cartilage
120
Epiphyseal plate function
growth
121
What type of tissue is the epiphyseal line made of?
bone
122
What steps of endochondral ossification occur in the embryo?
1. start with the cartilage model
2. the cartilage breaks down, blood vessels begin to grow, and the periosteum
3. primary ossification center begins to form in the diaphysis
123
What steps of endochondral ossification occur after birth?
4. the secondary ossification center begins to form on the ends of the bone (epiphysis)
5. articular cartilage and the epiphyseal plate form
6. when the bones stop growing the epiphyseal plate becomes the epiphyseal line
124
What are the two types of bone growth?
interstitial and appositional bone growth
125
When does bone growth begin?
begins during embryonic development
126
Which type of bone growth grows in length?
Interstitial bone growth
127
Interstitial bone growth mechanism
gradually replaces growing cartilage with bone within the epiphyseal plate
128
Which type of bone growth grows in width?
appositional bone growth
129
Appositional bone growth mechanism
- adds layers to the edge (osteoblasts)
- widens the medullary cavity (osteoclasts)
130
Bone remodeling
a continuous process affected by mechanical stress and hormones
131
Periosteum
The periosteum is a thin membrane on the outside of your bones. It serves to protect your bones but also has the ability to help them heal. It can even help your body grow new bone when damage occurs
132
Mechanical stress on bone
muscle contraction and gravity
133
What happens when mechanical stress increases?
osteocytes detect it which then stimulates osteoblasts to increase osteoid synthesis which ultimately increases bone strength
134
What happens if reduced mechanical stress is detected?
bone strength will be decreased through the reduction in the collagen formation and demineralization
135
What do hormones influence?
bone growth and bone remodeling
136
Define hormones
signaling molecules (chemicals) released into the blood and binding to the target cells' receptors to initiate response
137
Hormones: endocrine cells and target cells
signaling molecules from the endocrine cells bind to the receptors of the target cells
138
What hormones are involved in bone growth/remodeling?
growth hormone, sex hormone, calcitonin, and parathyroid hormone
139
When does bone growth stop?
25-26 years of age
140
Growth hormone response
growth hormones stimulate chondroblasts in epiphyseal plate increasing bone growth
141
What are examples of sex hormones?
estrogen and testosterone
142
Sex hormones response
sex hormones stimulate osteoblasts and chondroblasts increasing bone growth
143
Calcitonin response
calcitonin inhibits osteoclasts activity (bone resorption) increasing calcium in the bone and decreasing the blood calcium levels
144
Parathyroid hormone (PTH) response
stimulates osteoclasts activity (bone resorption) decreasing the calcium in bone and increasing blood calcium levels
145
When osteoclast activity is inhibited what happens?
less calcium is released into the blood and more calcium is left remaining in the bone
146
What kind of relationship is present between calcitonin and the parathyroid hormone?
antagonist (or opposites)
147
Blood calcium level regulation functions
- bone hardness
- muscle contraction
- exocytosis (vesicular transport)
- blood clotting
148
Calcium homeostasis
maintaining proper calcium levels in blood
149
Higher/lower levels of calcium are what?
lethal
150
What major organs help return calcium levels to a normal range?
bones, intestines, and kidneys.
151
Bones relationship with calcium
can be used to store calcium
152
Intestines relationship with calcium
absorbs calcium from food into the blood stream
153
Kidneys relationship with calcium
regulates the amount of calcium to be removed with the urine or retained in the blood
154
When blood calcium levels are high what hormone lowers it?
calcitonin
155
Calcitonin does what to the Ca2+ in bone, intestines and kidneys?
- Bone: Increases Ca2+ deposition
- Intestines: decreases Ca2+ uptake
- Kidneys: increases Ca2+ removal
156
When blood calcium levels are low what hormone raises it?
parathyroid hormone + calcitriol (vitamin D)
157
Parathyroid hormone does what to the Ca2+ in bone, intestines and kidneys?
- Bone: Increases Ca2+ release
- Intestines: increases Ca2+ uptake
- Kidneys: increases Ca2+ retention
158
What does deposition mean?
deposit (less in blood)
159
What are the effects of aging on bone?
loss of collagen and minerals
160
Loss of collagen and minerals in the bone results in what?
osteopenia
161
Osteopenia
the gradual/natural thinning of bones (weaker bones)
162
Osteoporosis (disease)
bone loss that compromises normal function
163
Normal bone mineral density levels
> -1.0
164
Osteopenia bone mineral density levels
-1.0 to -2.5
165
Osteoporosis bone mineral density levels
< -2.5
