Chapter 5 - The Skeletal System Flashcards
0
Q
Two divisions of the skeleton and their meanings
A
- Axial - head and center of body (skull, ribs, vertebral column)
- Appendicular - movement (limbs, pelvis)
1
Q
How many bones are in the body?
A
206
2
Q
Two types of bone tissue and their meanings
A
- Compact bone - dense smooth bone
2. Spongy bone - bone with open spaces within
3
Q
The skeletal system makes up how much of the body?
A
20% of total body mass
4
Q
Four components to the skeletal system
A
- Cartilage
- Bone
- Tendons
- Ligaments
5
Q
Functions of the skeletal system along with their specific meanings
A
- Protection
- Support - rigid structure
- Movement - bones act as levers
- Storage - Ca, P, and fat
- Blood cell production
6
Q
What does cartilage consist of?
A
- Cells
2. Extracellular matrix
7
Q
Cartilage cells
A
Chondrocytes
8
Q
Where are the chondrocytes found in cartilage?
A
Lacunae
9
Q
Two components to the extracellular matrix in cartilage
A
- Collagen and Elastic fibers
2. Ground substance of chondrotin sulfates
10
Q
What does cartilage lack and what is the cause of lacking this?
A
- Lacks arteries, veins, and lymphocytes
- It heals very slowly
11
Q
Types of cartilage
A
- Hyaline
- Elastic
- Fibrocartilage
12
Q
What is the most common but weakest cartilage?
A
Hyaline cartilage
13
Q
Structure and location of hyaline cartilage
A
Structure: Chondrocytes, chondroitin sulfate, some collagen
Location: Embryonic skeleton, Articular surfaces, respiratory passages, nasal septum, between ribs and sternum
14
Q
Structure and location of Elastic Cartilage
A
Structure: Chondrocytes, chondrotin sulfate, densely packed elastic fibers
Locations: auricle, tip and lateral walls of nose, epiglottis
15
Q
Most flexible type of cartilage
A
Elastic cartilage
16
Q
The strongest type of cartilage
A
Fibrocartilage
17
Q
Structure and location of fibrocartilage?
A
Structure: Chondrocytes, chondrotin sulfate, densely packed collagen fibers
Location: Intervertebral disc, pubic symphysis, articular cartilage in kneww
18
Q
Surrounds the cartilage
A
Perichondrium
19
Q
What is the perichondrium made out of?
A
Fibrous connective tissue
20
Q
What does the perichondrium provide?
A
- Support and protection
- New chondrocytes
21
Q
Where is the perichondrium located?
A
- Hyaline cartilage
- Elastic cartilage
22
Q
Where is the perichondrium absent?
A
- Articular surfaces
- Fibrocartilage
23
Q
The layers and the functions of the layers for the Perichondrium
A
- Outer: binds cartilage to adjacent tissues; provides support and protection
- Inner: For growth and maintenance
24
Six steps to appositional growth in cartilage
1. Starts in perichondrium
2. Mesenchymal cells form inner layer of perichondrium
3. Mesenchyme move toward matrix to become chondrogenic cells
4. Chondrogenic cells aggregate and become chondroblasts
5. Chondroblasts secrete matrix which forces cells apart
6. Chondroblasts become enclosed in matrix and become chondrocytes
25
Three steps to Interstitial growth
1. Chondrocytes are enclosed in matrix and divide
2. As they move apart, matrix forms in between them
3. Growth of cartilage from within
26
Three characteristics of Osseous tissue
1. Made of supportive CT
2. Contains specialized cells
3. Solid extracellular matrix
27
What is the solid extracellular matrix in osseous tissue composed of?
1. Osteoid - organic portion, protein fibers
2. Ground substance - Ca salts
3. Water
28
Order of the creation of bone cells
1. Osteoprogenitor
2. Osteoblasts
3. Osteocytes
29
What do osteoprogenitor cells do?
1. Mesenchymal cells
2. Predecessor to osteoblasts
3. Play role in initial bone growth and fracture repair
30
Increased osteoblast activity equates to what?
Stronger bone
31
Characteristics and derivations of osteoblasts?
- Derived from osteogenic cells and predecessor to osteocytes
- Secrete osteoid
- Common in growing bone
32
Characteristics of osteocytes
1. Mature cells
2. Exist within matrix
3. Maintain Ca and PO4 homeostasis
4. Found in spaces called lacunae
33
Break down of bone
Osteolysis
34
Cells involved in osteolysis
Osteoclasts
35
Increase in osteoclast activity equate to what?
Weaker bone
36
How do osteoclasts form?
They form from the fusion of many white blood stem cells
37
Two components that make up the bone matrix
1. Inorganic materials
| 2. Osteoid
38
What composes the inorganic materials in the bone matrix?
1. Brittle salts - Hydroxyapatite, calcium carbonate, ions
39
How much of the bone matrix is composed of inorganic materials?
65%
40
What are the things that up the osteoid in the bone matrix?
1. Organic
| 2. Collagen, glycoproteins, and proteoglycans
41
What percentage of the cell matrix in bone is composed of osteoid?
35%
42
What are the two prominent qualities to the bone matrix?
Flexible because of the fibers
| Strong because of the inorganic materials
43
Two types of bone
1. Compact
| 2. Spongy
44
How is compact bone arranged?
in Osteons
45
How is spongy bone arranged?
Arranged in trabeculae
46
Osteoctyes communicate through ____
Canaliculi
47
What do canaliculi do?
Radiate outward and connect one cell to the next cell in compact bone
48
A unit of compact bone
Osteon
49
Three structural components to osteons
1. Concentric lamellae of matrix surrounding a central (Haversian) canal
2. Contains blood vessels and nerves
3. Osteons connected to each other by perforating canals
50
Three different kinds of lamellae
1. Concentric
2. Interstitial
3. Circumferential
51
- Layers of bone surrounding the central canal
| - Make up osteons
Concentric lamellae
52
- Found between the osteons
| - Represents older osteons partially removed during tissue remodeling
Interstitial lamellae
53
- Surrounded the compact bone
| - Directly produced from periosteum
Circumferential
54
What does spongy bone (cancellous) contain?
- Trabeculae
- Ostecytes in lacunae
- Canaliculi
- Matrix
55
What does spongy bone not contain?
Osteons and central canal
56
Latticework of thin plates of bone oriented along lines of stress
Trabeculae
57
The spaces on trabeculae are filled with what?
Bone marrow where blood cells develop
58
Where is trabeculae found?
Found in ends of long bones and inside flat bones
59
What does trabeculae do?
Lightens the bone and allows for movement
60
Encloses bone
Periosteum
61
Where is periosteum absent?
- Site of attachment of muscles, tendons, and ligaments
| - Instead, surface are covered by articular cartilage
62
Two layers of the periosteum and their respective jobs
1. Outer fibrous: gives rise to collagen
| 2. Inner: for growth or new cells and maintenance
63
One cell layer that covers surfaces of spongy bone and medullary cavity
Endosteum
64
Cell types in the endosteum
- Osteogenic, osteoblasts, and osteoclasts
65
Five components to the anatomy of a long bone
1. Diaphysis
2. Epiphysis
3. Metaphysis
4. Articular cartilage
5. Medullary cavity
66
Shaft of a long bone
Diaphysis
67
One end of a long bone
Epiphysis
68
Growth plate region of a long bone
Metaphysis
69
Over joint surfaces and acts as friction and shock absorber
Articular cartilage of a long bone
70
Marrow cavity of a long bone
Medullary cavity
71
Two types of bone marrow
Yellow and red
72
Components to red bone marrow
1. Areolar and myeloid tissue
| 2. Produces all types of blood cells
73
Locations of red bone marrow
In medullary cavities of infants and in spongy bone in adults
74
Four components to yellow bone marrow
1. Composed of arelolar and adipose CT
2. In medullary cavity of long bones
3. Energy storage
4. Absent in infants
75
Supplies arteries with blood and nerve supply
Periosteal arteries
76
- Enter through nutrient foramen
| - Supplies compact bone of diaphysis and yellow marrow
Nutrient arteries
77
Nutrient arteries enter through _____
Nutrient foramen
78
Supply red marrow and bone tissue of epiphyses and metaphyses
Metaphyseal and epiphyseal arteries
79
All arteries have corresponding _____
Veins
80
Replacing CT with bone
Ossification
81
Mesenchymal cells -> spongy bone
Intramembranous
82
Hyaline cartilage -> spongy bone
Endochondral
83
When does intramembranous ossification begin and end?
Begins at about week 8 in embryo and finishes by week 15
84
What does the intramembranous ossificiation form?
- Cranial flat bone
- Facial bones
- Dentary bones
- Clavicle
- Sesmoid bones
85
Location where bone growth begins
Primary ossification center
86
Steps to intramembranous ossification
1. Primary ossification center
2. Mesenchymal cells arrange around blood vessels
3. Bone morphogenic proteins released
4. Mesenchymal cells are recruited, divided, and differentiated into osteoblasts
5. osteoblasts secrete osteoid
6. Osteoblasts become isolated and turn into osteocytes
7. Produce spicules of bone that interconnect
8. Mesenchymal cells at surface form inner layer of periosteum
9. Calcified matrix is degraded by osteoclasts to form spongy bone
10. End = spongy bone covered with thin layer of compact bone
87
When bone replaces a cartilage model
Endochondral Ossification
88
When does endochondral ossification begin?
Week 7 of embryo
89
What does endochondral ossification
- Long bones
- Most short bones
- Non-cranial irregular and flat bones
- Middle ear ossicles
90
Steps to endochondral ossification
1. Hyaline cartilage forms model of future bone
2. Cartilage enlarges; chondrocytes near center hypertrophy
3. Blood vessels grow around and penetrate cartilage
4. Cells differentiate into osteoblasts
5. Compact bone forms around the diaphysis
6. Spongy bone forms in the primary ossification center
7. Remodeling of the shaft
8. Formation of the medullary cavity
9. Length increases
10. Blood vessels penetrate the ends of the model
11. Secondary ossification centers form at both epiphyses
12. Ends with incomplete ossification of epiphysis
13. Some cartilage remains
91
What does it mean when the chondrocytes are near hypertrophy
1. Matrix reduced to struts
| 2. Chondrocytes deprived of nutrients and die
92
At the ends of endochondral ossification, what cartilage remains?
1. Articular cartilage - contact points of bone
| 2. Epiphyseal plate - growth plate
93
Explain the process of bone growth: elongation
1. Occurs at epiphyseal plate
2. Growth in length continues until 2 ossification centers meet
3. Relative thickness of epiphyseal plate does not change until growth complete
4. Cartilage depleted and epiphyseal plate narrows to epiphyseal line
94
Explain bone growth: appositional
1. Compact bone deposited beneath periostium
2. Bone thickens
3. Bone remodeling occurs throughout life (Due to osteoclasts and osteoblasts)
95
Continual redistribution of bone matrix along lines of mechanical stress
Bone remodeling
96
Why is bone remodeling ongoing?
Osteoclasts carve out small tunnels and osteoblasts rebuild osteons
97
What percentage of bone is remodeled each year?
4% compact bone and 20% of spongy bone
98
This bone is fully remodeled every 4 months
Distal femur
99
Two types of fractures in bones with their meanings
1. Closed (simple): break that does not penetrate skin
| 2. Open (compound): broken bone penetrates through skin
100
Fractures are treated by ____ and ____
Reduction and immobilization
101
Four ways for fractures to be repaired
1. Fracture hematoma
2. Fibrocartilage callus
3. Bony callus
4. Remodel tissue
102
Factors affecting growth, repair, and development
- Nutrition: Vit. D
- Sunlight
- Hormones: PTH, calcitonin, GH, thyroid hormone, sex hormones
- Physical stress
103
Abnormal reduction of bone mass
Osteoporosis
104
Reasons for osteoporosis
- Loss of estrogen at menopause
- Deficiency of minerals in youth
- Imbalance in activity between osteoblasts and osteoclasts
105
Explain the illness of fibrodysplasia ossificant progressiva and its affect on the body and treatment plan
- Fibrous tissue becomes ossified
- Genetic
- Injury results in inappropriate bone formation
- Early adulthood: freezing of major joints
- Early 20s: confined to wheel chair
- Starvation and pneumonia can result
- No treatment
