Bone Development & Connective Tissue Flashcards
1
Q
What are the primary functions of bone tissue?
A
- Structure
- Locomotion
- Protection
- Calcium homeostasis
- Hematopoietic
2
Q
What is the name for the shaft of a long bone?
A
Diaphysis
3
Q
What is physis?
A
A growth plate
4
Q
What is the name for the secondary ossification center on the non-weight bearing part of a long bone?
A
Apophysis
5
Q
What are some examples of apophyses?
A
Trochanters, tuberosities, etc.
6
Q
Where is the metaphysis of a long bone?
A
Next to the most metabolically active part of the bone, between diaphysis and epiphysis
7
Q
What is the name of the expanded end of a long bone?
A
Epiphysis
8
Q
Where is cortical bone found?
A
The outer shell of the bone
9
Q
What is trabecular bone?
A
Thin bone/cancellous bone
10
Q
What is the name of the less dense center of a long bone?
A
Medullary cavity
11
Q
Where does bone pain come from? Why?
A
Pain comes from periosteum because it is innervated
12
Q
When a physis fuses, what is left behind on the bone?
A
Physeal scar
13
Q
What percentage of bone composition is made up of cells?
A
About 10%
14
Q
What are four cells found in bone?
A
- Osteoprogenitor cells
- Osteoblasts
- Osteoclasts
- Osteocytes
15
Q
What percentage of bone is organic?
A
About 30%
16
Q
What is the primary organic component in bone tissue?
A
Type I collagen (about 88%)
17
Q
What is the function of type I collagen in bone?
A
Resists tensile forces
18
Q
Osteocalcin is a byproduct of ___
A
osteoblasts
19
Q
What is the function of osteopontin and sialoprotein?
A
Anchor cells to matrix, work to adhere things
20
Q
What are the organic components of bone?
A
- Type I collagen
- Osteocalcin
- Osteopontin and sialoprotein
21
Q
What is the function of the organic components of bone?
A
- Contribute to tensile strength
- Make bone more elastically and/or plastically responsive to stress
22
Q
What constitutes the inorganic component of bone tissue?
A
- Hydroxyapatite: Ca10(PO4)6(OH)2
- Carbonate, citrate, flouride, chloride, sodium, magnesium, potassium, and strontium
23
Q
What is the function of the inorganic components of bone?
A
- Contributes to rigidity of bone tissue
- Lends compressive strength to bone tissue
24
Q
What do osteoprogenitor cells develop into?
A
Osteocytes or osteoblasts
25
Where are osteoprogenitor cells found?
Bone marrow and periosteum
26
What is produced by osteoblasts?
* Produces and mineralizes bone tissue
* Alkaline phosphatase and osteocalcin
* Several growth factors
27
What growth factors are produced by osteoblasts?
* IL-1
* FGF
* IGF-1
* IGF-2
(and others)
28
What is the function of osteoblasts?
Controls the differentiation and maturation of osteoclasts (production of RANKL)
29
What are osteoclasts?
Multi-nucleated cells in the monocyte/macrophage cell family
30
What is the function of osteoclasts?
Bone resorption using lysosomes and hydrolytic enzymes
31
What substances signal to increase osteoclastogenesis?
Rank and RankL
32
What is the ratio of organic to inorganic bone components in children?
1:1
33
What is the ratio of organic to inorganic bone components in adults?
1:4
34
What is the ratio of organic to inorganic bone components in elderly?
1:7
35
How do changes in organic to inorganic components affect the properties of bone?
Decreased elasticity over time
36
A greater relative organic component produces ___
increased elasticity and plasticity in response to stress
37
Where is the para-physiological space in the stress/strain curve?
Elastic region
38
Where does permanent deformity occur in the stress/strain curve?
Plastic region (after yield point)
39
When does failure/fracture occur in the stress/strain curve?
After the plastic region (ultimate yield point)
40
Which type of bone is most responsible for preventing fractures?
Trabecular/spongy bone
41
How does cortical/compact bone present in a stress/strain curve?
High stress with little strain percentage
42
Does bone have more tensile or compressive strength?
More compressive strength than tensile
43
Unmineralized bone is called ___
osteoid
44
Compact and spongy bone are both ___ bone
lamellar (layered)
45
What are three types of compact bone?
* Circumferential bone
* Concentric lamellar bone
* Interstitial lamellar bone
46
What is the histology of woven bone?
* Irregular arrangement of type I collagen fibers
* Many osteocytes of different size and shape
47
What is the nature of woven bone?
* Deposits rapidly
* Low tensile strength
* Response to stress in adults
48
A tissue histologically presents with an irregular arrangement of type I collagen fibers among many osteocytes of different size and shape
What type of bone is this?
Woven bone
49
What gives rise to bone?
Mesenchymal condensation
50
In what two ways does mesenchymal condensation give rise to bone?
* Intramembranous ossification
* Endochondral ossification
51
During intramembranous ossification, how does mesenchyme give rise to bone?
Direct transition from mesenchyme to bone
Grows via accretion, outward from a primary center of ossification (adding bone to the surface and edges)
52
The closure of the fontanels is an example of what type of ossification?
Intramembranous ossification
53
During endochondral ossification, how does mesenchyme give rise to bone?
A cartilage model forms from mesenchyme, then is ossified
54
When do physes close?
Toward the end of puberty, varies by joint
55
How does the growth plate close in endochondral ossification?
Rate of ossification exceeds epiphyseal cartilage proliferation
56
When do females' bones stop growing in comparison to males'?
About 3 years earlier in females than males
57
What is bone modeling?
The process of original bone development
58
What is bone remodeling?
The continual process of bone turnover
59
What theory guides bone remodeling?
Wolff's Law:
Increased compressive forces = increased deposition
Decreased compressive forces/increased tensile forces = resorption
60
What are the requirements for remodeling bone?
* Maintain an equilibrium of calcium and other metabolites in blood and bone
* Viable blood supply to oxygenate bone cells
* Stress, pressure, or load on the bone
61
Without loading stresses, osteoclastic activity ___ and osteoblastic activity ___
osteoclastic activity **increases** and osteoblastic activity **decreases**
62
Which cells initiate bone remodeling?
Osteoclasts
63
During endochondral ossification, what step is required for ossification of cartilage to occur?
Vascularization
64
Collagen comprises ___% of all mammalian protein
25%
65
Which organs contain collagen?
Nearly all organs
66
What is the function of collagen in organs?
* Holds cells together
* Gives tissue structural integrity
67
What are the types of collagen and where are they found?
* Type I - bone
* Type II - cartilage
* Type III - reticular (skin, muscles, blood vessels, along with type I)
* Type IV - basement membrane
68
What cells produce collagen?
All cells of the fibroblast family:
* bone cells (osteoblast/osteocyte)
* cartilage cells (chondrocyte)
* fat cells (adipocyte)
* smooth muscle cells
69
Fibroblasts are derivative of ___
mesoderm
70
How are fibroblasts classified?
Staining, morphology, and function
71
What is the least specialized cell in the body?
Fibroblasts, the most versatile of connective tissue cells, able to differentiate into others
72
Which components of the extracellular matrix are secreted by fibroblasts?
* Collagen
* Proteoglycans
* Elastin
* Fibronectin and other structural proteins
73
What is the name for inactive fibroblasts?
Fibrocytes
74
What are the steps for intracellular collagen synthesis?
Amino acid synthesis -->
Alpha chain formation -->
Procollagen formation -->
75
What are the steps for extracellular collagen synthesis?
Tropocollagen formation -->
Organization and mature collagen arrangement
76
What are some possible signs/symptoms a patient may have if they suffer from a collagen synthesis disorder?
* Ligamentous laxity
* Joint hypermobility
* Vessel fragility
* Compromise of bone structural integrity
* Tooth loss/developmental issues
77
What are signs that a collagen synthesis disorder is causing vessel fragility?
Bleeding and/or bruising
78
The signs/symptoms of collagen synthesis disorders and their severity depends on what factor?
Where the disruption/problem occurs in collagen synthesis
79
Many will have a ___ etiology that will lead to disruption of normal collagen synthesis
genetic
80
What is Ehler's-Danlos?
"Rubber band syndrome"
Problem with procollagen peptidase (inability to cleave off terminal extensions)
This is a contraindication to manipulation
81
Which collagen disorder possesses a problem with procollagen peptidase leading to inability to cleave off terminal extensions?
Ehler's-Danlos
82
What is Marfan's syndrome?
Hereditary issue affecting cross-linking in collagen synthesis
Not an adjusting candidate
83
Which collagen disorder is a hereditary issue affecting cross-linking in collagen synthesis?
Marfan's syndrome
84
What is osteogenesis imperfecta?
Collagen synthesis disorder due to messenger RNA transcription deletion error
85
Which collagen disorder possesses a messenger RNA transcription deletion error?
Osteogenesis imperfecta
86
What are some genetic etiologies of collagen synthesis disorders?
Which of these are more common?
Ehlers-Danlos and Marfan's syndrome are very common
A less common etiology is osteogenesis imperfecta
87
What is an example of an environmental etiology of collagen synthesis disorders?
Scurvy: hydroxylation step interrupted
88
Which collagen disorder involves the hydroxylation step being interrupted?
Scurvy
| environmental etiology
89
Collagen is a major fibrous element in:
* Bone
* Skin
* Teeth
* Tendons
* Cartilage
* Blood vessels
90
# alignment
What are some terms relating to peripheral alignment?
* Subluxation
* Dislocation
91
# alignment
What are some terms relating to spinal alignment?
* Lordosis
* Kyphosis
* Anterolisthesis
* Scoliosis
* Etc.
92
View:
Anatomy:
Skeletally young/mature:
View: AP knee
Anatomy: femur, patella, tibia, fibula
Skeletally young/mature: mature
93
What is the alignment of this knee?
Lateral and superior (proximal) dislocation of tibia (in relation to femur)
94
What notes can be made about the bones in this knee?
Connective tissue?
Bone: missing medial condyle of femur, spines of tibia, and patella; some bones are more radiolucent than others
CT: cartilage not visualized; none left after dislocation
95
What notes can be made about the soft tissue in this knee?
Radiodense soft tissue superior to patella; mineral composition or edema/debris
96
What does radiodensity in this knee suggest?
Usage (Wolff's law)
97
Does this patient likely feel pain when walking on this knee?
Likely can't feel the knee
98
View:
Anatomy:
Skeletally young/mature:
View: lateral knee
Anatomy: femur, tibia, fibula, patella (yet to form)
Skeletally young/mature: young (growth plates observed)
99
Is this knee lesion local or systemic?
Local
100
What notes can be made about alignment of this knee?
Normal alignment
101
What notes can be made about the bones of this knee?
Extremely radiodense/osteoblastic in inferior diaphysis of femur
102
What notes can be made about connective tissue in this knee?
Soft tissue?
No observations about cartilage or soft tissue
103
What are the primary growth centers of a long bone?
Diaphysis & metaphysis
104
What are the secondary growth centers of a long bone?
Epiphysis & apophysis
105
What is the most metabolically active part of a long bone?
Metaphysis
106
Is the diaphysis of a long bone metabolically active?
No, inactive
107
Is the epiphysis of a long bone metabolically active?
Yes, but less active than metaphysis
108
What is the dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles?
Periosteum
109
What is the inner membrane layer separating the marrow cavity and the cortical bone?
Endosteum
110
What percentage of bone is composed of inorganic material?
60%
111
What bone cell is found in the marrow and periosteum and can develop into osteocytes or osteoblasts?
Osteoprogenitor cell
112
What is the term for an osteoblast embedded in bone matrix (lacunae) that maintains bone tissues?
Osteocyte
113
# stress strain curve
Compared to normal adult bone, what bones would have a more gradual slope, with a **longer** plastic phase?
Bones of children
(more organic material)
114
# stress strain curve
Compared to normal adult bone, what bones would have a more gradual slope, with a **shorter** plastic phase?
Bones with osteoporosis
(more inorganic material, likely older)
115
What are the major passageways running in the direction of the length of long bones, providing paths for blood vessels?
Haversian canals
116
What are the connections between Haversian canals that runs in a perpendicular fashion?
Volkmann's canals
117
According to Wolff's law, what type of force will increase bone **resorption**?
Increased tensile force (less compressive)
118
According to Wolff's law, what type of force will increase bone **deposition**?
Increased compressive force (less tensile)
119
What is the term for the remodeling unit of bone?
Cutting cone
120
What is the structural organization of collagen?
Fibrils within fibers within bundles
121
Fibroblasts will differentiate into ____ when the environment is anoxic
chondrocytes (cartilage cell)
122
During collagen synthesis, what materials are necessary for hydroxylation to occur?
Iron, oxygen, and vitamin C
123
What must occur in order to turn procollagen into tropocollagen?
Cleavage of terminal extensions of procollagen
124
What enzyme is responsible for the creation of tropocollagen?
Procollagen peptidase
