Lecture #11 Chapter 7 Flashcards
1
Q
What are bones?
A
Bones are the organs of the skeletal system
2
Q
What 5 different tissues are bones comprised of?
A
-Bone tissue
-Cartilage
-Dense connective tissue
-Blood
-Nervous tissue
3
Q
What are the 4 functions of bones?
A
-Support and protect softer tissues
-Provide points of attachment for muscles
-House blood-producing cells
-Store inorganic salts
4
Q
What are the 2 ways that bones vary greatly?
A
-Size
-Shape
5
Q
What are the 3 features that bones are similar in?
A
-Structure
-Development
-Function
6
Q
What are the 4 classifications of bones?
A
-Long bones
-Short bones
-Flat bones
-Irregular bones
7
Q
What are the 3 characteristics of long bones?
A
-Long
-Narrow
-Have expanded ends
8
Q
What is the characteristic of short bones?
A
It is cubelike (length=width)
9
Q
What is the characteristic of flat bones?
A
Plate-like with broad surfaces
10
Q
What are the 2 characteristics of irregular bones?
A
-Variety of shapes
-Most are connected to other bones
11
Q
What is a sesamoid bone?
A
Any of the round bones that form within tendons adjacent to joints
12
Q
Epiphysis?
A
Expanded end
13
Q
Diaphysis?
A
Bone shaft
14
Q
Metaphysis?
A
Between diaphysis and epiphysis, the widening part
15
Q
Articular cartilage?
A
Cover epiphysis
16
Q
Periosteum?
A
Encloses bone; dense connective tissue
17
Q
What is another name for compact bone?
A
Cortical bone
18
Q
Where is compact/cortical bone located?
A
Wall of the diaphysis
19
Q
What is another name for spongy cone?
A
Cancellous bone
20
Q
Where is spongy/cancellous bone located?
A
Makes up epiphyses
21
Q
Trabeculae?
A
Branching bony plates that make up spongy bone
22
Q
Medullary cavity?
A
Hollow chamber in the diaphysis that contains marrow
23
Q
Endosteum?
A
A thin membrane containing bone-forming cells that line the medullary cavity as well as spaces within spongy bone
24
Q
Bone marrow?
A
Comes in two types, red and yellow. Lines medullary cavity and fills spongy bone spaces
25
Osteocytes?
Mature bones cells
26
Lacunae?
A small chamber or cavity
27
Canaliculi?
Canals that connect the lacunae of bone tissue
28
What is the extracellular matrix of bone made of?
Collagen fibers and inorganic salts
29
What is the role of collagen fibers in bone?
Gives bone resilience
30
What is the role of inorganic salt in bone?
Makes the bone hard
31
What is collagen fiber?
A white fiber consisting of the protein collagen that is common in connective tissues and bone matrix
32
What does compact bone consist of?
Cylindrical units called osteons
33
What is an osteon?
Cylinder-shaped units containing bone cells and matrix lamellae that surround a central canal (Haversian system)
34
What are the 4 functions/characteristics of compact bone?
-Strong
-Solid
-Weight-bearing
-Resists compression
35
What does spongy bone consist of?
Branching plates called trabeculae
36
What are the 2 characteristics/functions of spongy bone?
-Somewhat flexible
-Nutrients diffuse through canaliculi
37
What are perforating canals/Volkmann's canals?
Canals that connect central/Haversian canals
38
What are the canals called that connect adjacent central/Haversian canals?
Perforating canals/Volkmann's canals
39
What does compact bone consist of?
Osteons
40
What is an osteon?
A cylinder-shaped unit containing bone cells and matrix lamellae that surround a central canal (Haversian system)
41
What are the spaces called that osteocytes reside in?
Lacunae
42
Lamellae?
Layers of matrix around a central canal
43
What provides nutrients to bone tissue?
Blood vessels
44
What can osteocytes pass nutrients through?
Canaliculi
45
When does the skeletal system develop?
During the first few weeks of prenatal development
46
What are the 2 ways in which bone tissue replaces existing connective tissue?
Intramembranous bones and Endochondral bones
47
What is intramembranous ossification?
Flat skull bones are forming between sheets of primitive connective tissue (mesenchymal cells)
The process of replacing embryonic connective tissue to form intramembranous bone
48
What is endochondral ossification?
Long bones and most of the skeleton are formed from hyaline cartilage models
49
What do intramembranous bones originate as?
Sheetlike layers of connective tissue
50
What are the general shapes of intramembranous bones?
Broad and flat bones
51
What are examples of intramembranous bones?
-Flat bones of the skull
-Clavicles
-Sternum
-Some facial bones (mandible, maxilla, zygomatic)
52
What are the 6 steps in intramembranous ossification?
1. Sheets of embryonic tissue (mesenchyme) appear at the sites of future bones
2. Mesenchymal cells in primitive tissue differentiate into osteoblasts which deposit bone matrix
3. Dense networks of blood vessels supply the developing spongy bone
4. Osteoblasts become completely surrounded by matrix and are then osteocytes in lacunae
5. Mesenchyme on the surface of each developing structure condense to form periosteum
6. Osteoblast on the inside of the periosteum deposit compact bone over the spongy bone
53
What do endochondral bones begin as?
Masses of hyaline cartilage
54
What are 6 examples of endochondral bones?
Most of the bones of the skeleton such as the femur, humerus, radius, tibia, phalanges, and vertebrae
55
What are the 7 steps in endochondral ossification?
1. Masses of hyalin cartilage form models of future bones
2. Chrondrocytes enlarge and lacunae grow
3. Cartilage tissue and matrix breaks down, chondrocytes die, and the periosteum develops
4. Blood vessels and differentiating osteoblasts from the periosteum invade the disintegrating tissue
5. Osteoblasts blasts form spongy bone fill the space occupied by cartilage
6. Osteoblasts beneath the periosteum deposit compact bone
7. Osteoblasts become osteocytes when fully encased by the bony matrix
56
Where is the primary ossification center?
Diaphysis
57
Where is the secondary ossification center?
Epiphysis
58
What is the hyaline cartilage model?
When future bones are fist formed as hyaline cartilage models
59
What is the epiphyseal plate?
Cartilaginous layers that remain between the diaphysis and the epiphysis (two ossification centers) of a long bone that grows, lengthening of a bone
60
What is an osteoblast?
A bone-forming cell (builds bone)
61
What is an osteoclast?
A cell that breaks down bone matrix (crushes bone/cleans out bone)
62
What is the growing region of bone that separates the diaphysis from the epiphysis?
Epiphyseal plate
63
What are the 4 layers of cartilage cells in the epiphyseal plate?
- Zone of resting cartilage
- Zone of proliferating cartilage
- Zone of hypertrophic cartilage
- Zone of calcified cartilage
64
What is the zone of resting cartilage?
The layer closest to the epiphysis comprised of resting cells; anchor epiphyseal plate to the epiphysis
65
What is the zone of proliferating cartilage?
Rows of young cells undergoing mitosis
66
What is the zone of hypertrophic cartilage?
Rows of older cells left behind when new cells appear. They thicken the epiphyseal plate lengthening the bone. Matrix calcified, cartilage cells/chondrocytes die
67
What is the zone of calcified cartilage?
A thin layer of dead cartilage cells and calcified matrix
68
What are cells that break down calcified matrix?
Osteoclasts
69
What are cells that invade, replacing cartilage with bone tissue?
Osteoblasts
70
What is a physiological feature that must remain for bones to continue to grow in length?
For the cartilage cells of the epiphyseal plate to remain active
71
What physiological feature is present when a bone can no longer grow in length?
Ossification centers meet and the epiphyseal plate ossifies
72
How does bone thicken?
By depositing compact bone on the outside under the periosteum
73
What is bone remodeling?
The opposing processes of deposition and resorption that occur on the surfaces of endosteum and periosteum
74
What is bone resorption?
Removal of bone by osteoclasts
75
What is bone deposition?
Formation of bone by osteoblasts
76
What percent of the skeleton is replaced each year?
10%-20%
77
What 4 factors affect bone development, growth, and repair?
-Nutrition
-Sunlight exposure
-Hormone levels
-Physical exercise
78
What is the role of Vitamin D in bone development, growth, and repair?
Calcium absorption
79
What is the role of Vitamin A in bone development, growth, and repair?
Osteoblast and osteoclast activity
80
What is the role of Vitamin C in bone development, growth, and repair?
Collagen synthesis
81
What is the role of growth hormone in bone development, growth, and repair?
Stimulates cartilage cell division
82
What is the role of thyroid hormone in bone development, growth, and repair?
Causes replacement of cartilage with bone in epiphyseal plate, osteoblast activity
83
What is the role of parathyroid hormone (PTH) in bone development, growth, and repair?
Stimulates osteoclast activity/bone breakdown
84
What is the role of sex hormones (estrogen & testosterone) in bone development, growth, and repair?
Promotes bone formation, stimulates ossification of epiphyseal plates
85
What is the role of physical stress in bone development, growth, and repair?
Stimulates bone growth
86
What does a deficiency in vitamin D cause in bones?
Rickets and osteomalacia
87
What does a deficiency in vitamin A cause in bones?
Retards bone development
88
What does a deficiency in vitamin C cause in bones?
Slender and fragile bones
89
What does insufficiency of growth hormone cause in bones?
Pituitary dwarfism
90
What does excess of growth hormone cause in bones?
Gigantism in children and acromegaly in adults
