Bone Development Histology Flashcards
(132 cards)
1
Q
Process of bone ossification
A
Osteogensis
2
Q
What are the two types of ossification?
A
Intamembranous and Endochondral
3
Q
- No hyaline cartilage model precursor
- Mesenchyme to Bone
A
Intanmembranous Ossification
4
Q
- Hyaline cartilage model precursor
- Mesenchyme to Hyaline to Hyaline cartilage to Bone
A
Endochondral Ossification
5
Q
What type of tissue is bone?
A
Connective
6
Q
What does bone arise from?
A
Mesenchyme
7
Q
When does intramembranous ossification occur?
A
8th week of gestation
8
Q
Hyaline cartilage takes on initial shape of bone as well as bones place in the body
A
Hyaline cartilage model
9
Q
A- Ossification centers form within thickened regions of mesenchyme
B- Osteoid endergoes calcification
C- Woven bone and surrounding periosteum form
D- Lamellar bone replaces woven bone, as compact and spongy bone form
A
Intramembranous ossification
10
Q
Where is spongy bone formed?
A
Between 2 layers of compact bone
11
Q
What is one characteristic of all connective tissues?
A
They arise from embryonic connective tissue called mesenchyme
12
Q
Leads to the production of flat bones of the skull and the bones of the face
A
Intramembranous Ossification
13
Q
Woven or immature bone
A
Primary
14
Q
Lamellar or mature bone
A
Secondary
15
Q
Eroded and replaced with bone
A
Hyaline cartilage model
16
Q
Leads to the production of most short and long bones of the body
A
Endochondral ossification
17
Q
When are the first hyaline cartilage models visible?
A
6th week of gestation
18
Q
When are ossification centers of long bones of the limns present?
A
By 12th week of gestation
19
Q
In intramembranous ossification, Elongated, pale-staining, mesenchymal cells cluster and differentiate to
A
Osteoprogenitor cells
20
Q
In intramembranous ossification, What happens when cells differentiate into osteoprogenitor cells?
A
They become more rounded, while their cytoplasm changes from eosinophilic to basophilic
21
Q
What is the basophilic cytoplasm change a result of?
A
More rough ER
22
Q
What do osteroprogenitor cells differentiate into?
A
Osteoblasts
23
Q
What do clusters of osteoblasts create?
A
The ossification center
24
Q
Organic extracellular matrix
A
Osteoid
25
What secrete osteoid?
Osteoblasts while creating the ossification center
26
Where are calcium and other mineral salts deposited during calcification?
Around the framework of collagen fibers
27
Cells that are trapped in the calcifying osteoid
Osteocytes
28
Where do osteocytes sit?
In lacunae
29
Produced in small irregularly shaped pieces or spicules that are increased in size by apposition growth
Woven bone in Intramembraous ossification
30
Growth along the surface
Apposition growth
31
Small patches of bone production merge together to produce
A labyrinth of woven bone
32
The spaces between the bone spicules that are infiltrated with embryonic blood vessels differentiate into
Red bone marrow
33
The mesenchyme at the periphery of the bone condenses and forms the
Periosteum
34
What is woven bone replaced by?
Lamellar bond
35
What does lamellar bone form in intramembranous ossification?
Compact and spongy bone
36
Loosely organized embryonic connective tissue
Mesenchyme
37
Elongated, pale-staining, undifferentiated cells
Mesenchymal cells
38
Thin cytoplasmic processes
Mesenchymal cells
39
1. Fetal hyaline cartilage model develops
2. Cartilage calcifies and a periosteal bone collar forms around the diaphysis
3. Primary ossification center forms in the diaphysis
4. Secondary ossification centers form in the epiphysis
5. Bone replaces cartilage except the articular cartilage and epiphyseal plates
6. Epiphyseal plates ossify and form epiphyseal lines
Endochondral ossification
40
In endochondral ossification, mesenchymal cells aggregate and differentiate into
Chondroblasts
41
Secrete matrix, including type II collagen and produce the hyaline cartilage model
Chondroblasts
42
Formed from the mesenchyme where bone is going to form and in a similar shape
Hyaline cartilage model
43
How does hyaline cartilage grow?
Interstitial growth and appositional growth
44
What causes interstitial growth in endochondral ossification?
Activity of chondrocytes located in lacunae
45
What causes appositional growth in endochondral ossification?
Activity of chondroblasts at the surface
46
Where does a bone collar form in endochondral ossification?
Around the diaphysis
47
What does the perichondrium near the nid-region of the cartilage model contain?
Progenitor cells that differentiate into osteoblasts
48
When does perichondrium become functional periosteum?
When Progenitor cells differentiate into osteoblasts instead of chondroblasts
49
What creates a bone collar around the mid-section of the hyaline cartilage model?
Osteoblasts that secrete osteoid, that becomes calcified
50
How does the bone collar effect underlying cartilage?
Impedes the diffusion of oxygen and nutrients
51
In the mid-region begin to accumulate glycogen, undergo hypertrophy (swell up) and produce alkaline phosphatase
Chondrocytes
52
Compress the matrix and signal the surrounding matrix to calcify
Changes to chondrocytes in mid-region from formation of bone collar
53
What is hyaline cartilage primarily made of?
Type II collagen
54
What is bone primarily made of?
Type I collagen
55
What color does calcified hyaline cartilage stain with H and E stain?
blue/purple
56
What color do newly formed bones stain with H and E stain?
pink/red
57
What cannot take place through calcified cartilage matrix
Diffusion, Chondrocytes can no longer get the nutrients they need
58
Why does the matrix break down?
No present chondrocytes
59
Capillaries and osteoprogenitor cells from the new periosteum penetrate the
Bone collar and grow into the disintegrating calcified cartilage location
60
What does the penetration of the bone collar and growth into calcified cartilage induce?
The creation of the primary ossification center
61
What is important for the development of the bone marrow for the medullary cavity?
Blood vessels entering open space at the core of the diaphysis
62
Differentiate into osteoblasts at the opening space at the core of the diaphysis
Osteoprogenitor cells
63
Deposit bone matrix against the remnants of the calcified cartilage
Osteoblasts
64
Produced along the side of the remaining spicules of calcified cartilage
Woven bone
65
Eosinophilic
Primary bone
66
Basophilic
Calcified cartilage
67
No chondrocytes present in endochondral ossification
Calcified cartilage
68
Where is the primary ossification center found?
Diaphysis
69
Where it hylaine cartilage found when primary ossification center is present
Epiphyses
70
When do secondary ossification centers develop?
After birth
71
Where do secondary ossification centers form?
Epiphyses
72
Chondrocytes in epiphyses undergo
Hypertrophy
73
The cartilage matrix is compressed, the cartilage matrix calcifies, and the chondrocytes subsequently die: Which leads to
Opening up of spaces between spicules of calcified cartilage
74
Enter the spaces that have been opened up in the epiphyses and secondary ossification centers develop.
Blood vessels and osteoprogenitor cells
75
Hyaline cartilage is retained on the ends of the model and becomes
Articular cartilage
76
Used for cushioning of bone ends participating in joints
Articular cartilage
77
The remnant of hyaline cartilage between the epiphysis and the flared portion of the diaphysis is retained as the epiphyseal plate, which will be responsible for
Lengthwise growth of long bones
78
Flared portion of the diaphysis
Metaphysis
79
Epiphyseal cartilage is replaced with bone forming the
Epiphyseal line
80
What causes the formation of the epiphyseal line?
Hormone changes
81
Marks the end of growth in terms of height
End of puberty
82
The remnant of the last location of the epiphyseal plate.
Epiphyseal line
83
Long bones increase in ______ during infancy and youth
Length
84
What process allows bone to increase in length during infancy and youth?
Endochondral ossification at epiphyseal plate
85
Found between the epiphysis and the metaphysis
Epiphyseal plate
86
Composed of hyaline cartilage that can be divided into different zones
Epiphyseal plate
87
Zone 1
Zone of resting cartilage
88
Zone 2
Zone of proliferating cartilage
89
Zone 3
Zone of hypertrophic cartilage
90
Zone 4
Zone of calcified cartilage
91
Zone 5
Zone of ossification
92
Zone closest to the epiphysis
Zone of resting cartilage
93
Chondrocytes singularly or in very small groups
Zone of resting cartilage
94
Cartilage cells are undergoing mitosis and are stacking up like coins in line with the long axis of the bone
Zone of proliferation
95
Stacks of cartilage cells that look like coins
Isogenous groups
96
What do isogenous groups produce?
Matrix
97
Epiphysis is pushed away from the diaphysis causing the bone to lengthen in what zone?
Zone of proliferation
98
Chondrocytes increase in size.
Zone of Hypertrophy
99
- The cytoplasm of the chondrocytes accumulates glycogen.
| - The matrix is compressed/thinned due to the expansion of the cells.
Zone of Hypertrophy
100
The cartilage matrix begins to calcify through the formation of hydroxyapatite crystals.
Zone of Calcified Cartilage
101
Calcified cartilage matrix stains
Basophilic
102
The chondrocytes can no longer receive the nutrients they need via diffusion and they die because of
Calcified cartilage
103
This zone is in direct contact with marrow tissue, as it right next to the diaphysis.
Zone of ossification
104
Small blood vessels, blood cells, osteoprogenitor cells, and osteoclasts enter into the spaces previously occupied by the chondrocytes.
Zone of ossification
105
Bone (specifically primary/woven bone) is laid down by osteoblasts onto the calcified cartilage spicules that were left behind.
Zone of ossification
106
What does bone stain?
Eosinophilic
107
Eventually, much of this new bone and calcified cartilage will be eroded by the osteoclasts, so that secondary bone can be developed or to add space to the already existing medullary cavity.
Zone of ossification
108
The epiphyseal plate remains the same _____ during growth
Width
109
Cartilage growth must equal
Bone tissue replacement
110
At epiphyseal plate closure - hormones signal for the end of chondrocyte division and bone replaces all of the cartilage. Producing..
Epiphyseal line
111
Zone is composed of quiescent hyaline cartilage
Zone of resting cartilage
112
Chondrocytes have the characteristic appearance of stacking like coins along the long axis of the bone. Chondrocytes in this region are actively undergoing mitosis and matrix production. This causes the lengthening of the long bone
Zone of proliferation
113
Where chondrocytes undergo hypertrophy and compress the matrix.
Zone of hypertrophy
114
Where the cartilage matrix calcifies, the chondrocytes die, and spaces open up.
Zone of calcified cartilage
115
In this region, items such as blood vessels and osteoprogenitor cells enter into the now open spaces and osteoblasts start to produce primary (woven) bone.
Zone of ossification
116
Chondrocytes looklike they are being chased by
Bone cells
117
Appears that bone cells have caught up with chondrocytes
Epiphyseal plate closure
118
What happens to bone with appositional growth?
Increases in diameter and width
119
What happens at periosteal surface of bone in appositional growth?
Osteoblasts secrete bone matrix
120
What happens at endosteal surface of bone in appositional growth?
Osteoclasts breakdown bone matrix
121
Two controls impacting bone remodeling
- Negative feedback loop for maintenance of Calcium homeostasis
- Bone's response to mechanical stress and gravity
122
Impacts when remodeling occurs
Negative Feedback Loop of Maintenance of Calcium Homeostasis
123
Impacts where remodeling occurs
Bone's response to mechanical stress and gravity
124
Deposit and removal of bone
Bone remodeling
125
How much of your bone do you remodel every year?
5-10%
126
Controls for remodeling
Negative feedback loop, mechanical stresses and gravity
127
Maintains the homeostasis of a certain amount of Ca2+ in the blood through the release of the hormones calcitonin and parathyroid hormone
Negative feedback loop
128
Important in the blood as it is needed for many physiological processes.
Ca 2 +
129
What secretes calcitonin?
Parafollicular cells
130
Inhibits osteoclasts, and therefore bone resorption
Calcitonin
131
What secretes parathyroid hormone?
Parathyroid glands
132
Stimulates osteoclasts to resorb bone
Parathyroid hormone
