Unit 2 - Skeletal Flashcards
1
Q
What 4 components does the skeletal system contain?
A
- Bones
- Cartilage
- Ligament
- Connective Tissue
2
Q
Why is each bone considered an organ?
A
Bones contain: connective tissue, blood vessels, nerves, lymph vessels, cartilage, and connective tissue covering.
COMBINATION OF MANY TISSUE TYPES
3
Q
What are the 6 skeletal system functions?
A
- Support
- Protection
- Mineral storage
- Triglyceride storage
- RBC + WBC formation
- Leverage
4
Q
Where is the axial part of the body?
A
The middle or main part of the body.
5
Q
Where is the appendicular part of the body?
A
Limbs and connections of limbs to the axial division.
6
Q
Appendicular Girdle
A
Pectoral and pelvic connection points
7
Q
In what division is the skull?
- cranium
- face
A
Axial
8
Q
In what division is the hyoid?
A
Axial
9
Q
In what division are the auditory ossicles?
A
Axial
10
Q
In what division is the vertebral column?
A
Axial
11
Q
In what division is the thorax?
- sternum
- ribs
A
Axial
12
Q
In what division are the pectoral girdles?
- clavicle
- scapula
A
Appendicular
13
Q
In what division are the upper limbs?
A
Appendicular
14
Q
In what division is the pelvic girdle?
A
Appendicular
15
Q
In what division are the lower limbs?
A
Appendicular
16
Q
Describe the periosteum
A
- CT membrane covering external surface of bone
- Continuous with tendons + CT of joints
- Attached to bone matrix via perforating fibers
17
Q
Describe the endosteum
A
- Lining inner surfaces of bone; marrow cavity, trabecullae of spongy bone, canals of compact bone
18
Q
Describe the epiphysis
A
At the end of long bone. Contains red marrow.
19
Q
Describe the metaphasis
A
The connection point between the epiphysis and diaphysis.
20
Q
Describe the diaphysis
A
At the middle of a long bone. Contains yellow marrow.
21
Q
Where can spongy bone be found?
A
Epiphysis
22
Q
Describe the medullary cavity
A
Contains red and yellow marrow. Runs through epiphysis and diaphysis.
23
Q
What are the endosteum and periosteum important for?
A
Bone growth and remodeling
24
Q
What is the outer fibrous layer of the periosteum important for?
A
Protection
25
What is the inner osteogenic layer of the periosteum important for?
Growth and repair
26
Osteo means in correlation to...
Bone
27
Bone extracellular matrix is composed of...
Ground substance and fibers
28
What are osteogenic cells?
Immature starting cells; stem cells.
Formed from mesenchyme.
Develop into osteoblasts through mitosis and differentiation
29
What do osteoblasts do?
Build bone + bone matrix
30
What do osteocytes do?
Mature cells.
| Maintain bone tissue.
31
What do osteoclasts do?
Break down material.
| Functions in resorption + breakdown of bone matrix.
32
What two cells are important for bone remodeling?
Osteoblasts and osteoclasts
33
What is mesenchyme?
Embryonic connective tissue
34
What cells synthesize the organic components of the matrix?
Osteoblasts
35
Which cells initiate calcification?
Osteoblasts
36
What cells are involved in the maintenance of bone tissue?
Osteocytes
37
Which cells sense micro-damage and forces on bone to send repair signals?
Osteocytes
38
Which cells release enzymes and acids to degrade collagen and release minerals into blood?
Osteoclasts
39
Which cells are derived from myloid stem cells?
Osteoclasts
40
What are the organic components of bone ECM?
Ground substance and collagen fibers
41
What are the inorganic components of bone ECM?
Water and hydroxyapatite
42
What is hydroxyapatite?
Combination of minerals that fill spaces within collagen fibers.
43
What do collagen fibers contribute to bone?
Flexibility
44
What does hydroxyapatite contribute to bone?
Strength
45
If you remove minerals from bone, what happens?
Bone becomes rubbery, flexible
46
What happens if you remove collagen from bone?
Bone becomes brittle
47
What are trabeulae?
Irregular lattice of thin plates within spongy bone
48
Where can you find osteocytes?
Lacunae
49
What is the location of spongy bone?
- epiphysis of long bones
- surrounding marrow cavities
- flat, short, and irregular bones
50
What is the function of spongy bone?
- withstand forces from multiple directions
- lightens the skeleton
- contains red marrow for hemopoiesis
51
What is the location of compact bone?
- External layer of all bones
| - Diaphysis of long bones
52
What is the function of compact bone?
To give long bones the ability to withstand forces along longitudinal axis
53
What is a functional unit of compact bone?
An osteon
54
What are soft spots on the skull called?
Fontanels
55
In infants, what are long bones made of?
Cartilage
56
How long do epiphyseal plates stay as cartilage?
Until the end of puberty
57
Before birth, what are bones composed of?
- Mesenchyme ; loose connective tissue
| - Hyaline cartilage
58
What is ossification?
The replacement of connective tissue by bone
59
What type of ossification is from mesenchyme to bone?
Intramembranous
60
What type of ossification is from mesenchyme to cartilage to bone?
Endochondral
61
What process forms cranial bones?
Intramembranous ossification
62
What process forms the mandible?
Intramembranous ossification
63
What process forms the sternum?
Intramembranous ossification
64
What process forms the clavicle?
Intramembranous ossification
65
What process forms sesamoid bones?
Heterotropic
66
What are the steps to intramembranous ossification?
1. deposition of osteoid into mesenchyme
2. calcification of osteoid and osteocyte differentiation
3. formation of spongy bone trabeculae and periosteum
4. remodeling of outer spongy bone to compact bone.
67
What is calcification?
Deposition of calcium
68
What are the steps to endochondral ossification?
1. cartilage model forms
2. growth of cartilage model
3. blood vessels penetrate model and stimulate differentiation of osteogenic cells into osteoblasts
4. osteoblasts form bone on the outer surface of the model
5. osteoblasts create a primary ossification center - bone replaces cartilage.
6. osteoclasts create marrow cavity
7. spongy bone remodeled to compact bone.
8. around birth, secondary ossification center forms
9. spongy bone replaces cartilage at the epiphyses with the exception of epiphyseal plates and articular cartilage
69
What happens in primary endochondral ossification?
- marrow cavity formed
- cartilage is replaced with bone
- occurs before birth
70
Where is primary endochondral ossification located?
Diaphysis
71
What happens in secondary endochondral ossification?
- no marrow cavity
- some cartilage is left for epiphyseal plates and articular cartilage
- occurs around the time of birth
72
Where is secondary endochondral ossification located?
epiphyses
73
What do X-rays not show?
Cartilage
74
What grows bone length in children?
Epiphyseal Plate
75
What is interstitial growth?
- Growth from within cartilage
| - Growth in length @ epiphyseal plate
76
What is appositional growth?
- Growth at the outer surface
| - Growth in width
77
During interstitial growth what do mesenchymal cells differentiate into?
Chondroblasts
78
During interstitial growth what do chondroblasts differentiate into?
Chondrocytes
79
What cell divides in interstitial growth?
Chondrocytes
80
At what level of the epiphyseal plate do chondrocytes divide?
Proliferating cartilage
81
At what level of the epiphyseal plate do cells increase in size?
Hypertrophic cartilage
82
What are the 3 steps for fracture repair?
1. Fracture --> Hematoma
2. Fibrocartilage callus --> Bony callus
3. Bone remodeling
83
What 3 factors influence bone?
1. Dietary
2. Hormones
3. Exercise
84
What two minerals influence bone?
Calcium and phosphorus
85
How does vitamin A influence bone?
stimulate activity of osteoblasts
86
How does vitamin C influence bone?
Needed for collagen synthesis
87
How does vitamin D influence bone?
Stimulates calcium absorption
88
How do vitamin K and B12 influence bone?
Needed for synthesis of bone proteins
89
What is the goal of calcium homeostatis?
To regulate blood calcium within a normal range
90
What is the normal range of blood calcium?
8.5 - 11.0 mg/dl
91
What are three reasons calcium is physiologically important?
1. membrane excitability
2. intracellular activity
3. blood clotting
92
What are two ways calcium enters the blood?
Bone storage and intestinal absorption
93
How does calcium exit the body?
Kidney excretion
94
What function does calcitonin serve?
Decrease blood calcium
95
What is a stimulus for calcitonin?
High blood calcium
96
What hormone does the thyroid gland secrete?
Calcitonin
97
What is the target tissue of calcitonin?
Bone, kidney, and intestine
98
What is the goal of calcitonin?
To decrease blood calcium
99
What cell activity does calcitonin inhibit?
Osteoclasts
| Inhibit bone resorption
100
What is a stimulus for the parathyroid hormone?
Low blood calcium
101
What excretes the parathyroid hormone?
Parathyroid gland
102
What are the target tissues of the parathyroid hormone?
Bone, kidney, and intestine
103
What is the goal of the parathyroid hormone?
To increase calcium
104
What cell does the parathyroid hormone stimulate?
Osteoclast
| Increased bone absorption
105
What is the active form of vitamin D called?
Cacitriol
106
Describe vitamin D
A steroid hormone that is derived from cholesterol (hydrophobic)
107
What are the precursors to active vitamin D?
Cholecalciferol and Calcidiol
108
What cell does calcitriol (active vitamin D) stimulate?
Osteoclasts
109
What does calcitriol work with to stimulate absorption?
Parathyroid
110
What is the goal of calcitriol?
Increase blood calcium
111
Which people need higher levels of calcium per day?
Teenagers, pregnant women, and post menopausal women
112
Which two hormones act on osteoclasts?
Calcitonin and parathyroid
113
What two hormones act on osteoblasts?
Growth hormone (somatotropin) and estrogen/testosterone
114
What does growth hormone (somatotropin) stimulate?
Cell growth and protein synthesis (collagen)
115
What is the growth hormone stimulation process?
Stimulates insulin like growth factors --> Osteoblasts --> bone formation
116
Describe pituitary dwarfism
Low levels of growth hormone
| --> slow epiphyseal growth
117
Describe achondroplastic dwarfism
normal GH levels, failure of cartilage growth at epiphyseal plate, only affects long bones
118
Describe pituitary giantism
hyper secretion of GH in childhood causing accelerated epiphyseal growth
119
Describe acromegaly
hyper secretion of GH after puberty causing appositional growth
120
What do estrogen and testosterone stimulate?
Osteoblasts
| Bone formation
121
What hormones increase at puberty?
estrogen and testosterone
122
What do increased levels of estrogen and testosterone cause?
Bone growth / growth spurts
123
Bone will change in response to what?
Stress
124
What is the muscle pulling on bone force called?
Joint reaction
125
What is the impact for on bones called?
Ground reaction forces
126
Spongy bone is more metabolically active meaning...
it can respond to changes in mechanical loading more readily
127
Most likely places to fracture due to high spongy content:
Hip, wrist, spine
128
What does exercising early in life lead to?
Increase in peak bone mass
129
What does exercising later in life cause?
prevention of bone loss
130
Why does exercising prevent falls?
Improved strength and balance
131
Explain why exercising creates higher bone formation than absorption...
The mechanical force on bone signal the osteocytes to increase calcium and proliferation of osteoblasts
132
Describe osteoporosis
Porous bones
Reduced bone mass
Increased risk of fractures
133
How does bone change in osteoporosis?
The proportion of collagen and minerals is normal, but there's a decrease in bone mass
134
What causes reduced bone mass?
Any factor that stimulates bone resorption or inhibits bone formation
135
Define articulation
A point of contact between bone, cartilage, and teeth
136
What is an immovable joint called?
synarthrosis
137
What is a slightly movable joint called?
Amphiarthrosis
138
What is a freely movable joint called?
Diarthrosis
139
What type of joints are sutures between skull bones?
Fibrous synarthroses
140
What types of joints are teeth in sockets?
Fibrous synarthroses
141
All diarthroses are what joints?
synovial
142
Describe fibrous joints
synarthrosis
| Adjacent bones are joined by collagen fibers from one bone that penetrate into the other bone
143
Describe cartilaginous bones
Amphiarthrosis
| Two bones linked by cartilage
144
What are the two types of cartilaginous joints?
Synchondroses and symphyses
145
Describe synovial joints
Diathrosis
A point where two bones are separated by a narrow, encapsulated space filled with lubricating synovial fluid.
Most are freely mobile.
146
What is the difference between chondroblasts and osteoblasts?
Chondroblasts - growth and development of cartilage
| Osteoblasts - growth and development of bone
