Lecture 2/3 - Bone and Cartilage Flashcards
1
Q
What is the characteristic of the CT cartilage?
A
Specialized w/ abundance of ECM
2
Q
What is the composition of ECM in cartilage?
A
Firm, w/ GAG’s, proteoglycans, and collagen fibers
3
Q
Why is the ECM of cartilage firm?
A
Bears a lot of mechanical stress
4
Q
What do PG’s interact with?
A
the collagen fibers
5
Q
What are the three type of cartilages?
A
Hyaline, Elastic, and Fibrocartilage
6
Q
What kind of blood support does cartilage have?
A
Avasular, relies heavily on CT for diffusion
7
Q
What is missing (2 things) from cartilage?
A
Lymphatics and innervation
8
Q
What are present in lacunae?
A
Chondrocytes
9
Q
What do chondrocytes do?
A
secrete ECM
10
Q
What are the layers of the perichondrium?
A
Outer fibrous layer and inner cellular layer
11
Q
What are the characteristics of the fibrous layer?
A
Dense CT, collagen, fibroblasts, and avascular
12
Q
What type of collage is in the fibrous layer?
A
Type 1 collagen
13
Q
What is the perichondrium?
A
CT surrounding elastic and SOME hyaline cartilage
14
Q
What is present within the cellular layer?
A
Chondrogenic cells
15
Q
What are chondrogenic cells?
A
cartilage stem cells
16
Q
Why is the perichondrium important?
A
appositional growth, maintenance, and some repair
17
Q
What can chondrocytes form?
A
Isogenous groups since they are mitotic
18
Q
What cells secrete ECM in cartilage?
A
Chondrocytes and chondroblasts
19
Q
What type of collagen do ALL cartilage types contain?
A
Type II
20
Q
What other collagen type does fibrocartilage have?
A
Type I collagen
21
Q
What other collagen type does elastic cartilage have?
A
elastic
22
Q
What do PG’s do?
A
Shock absorbers, resist compression
23
Q
Why is it beneficial that they interact with Type II fibers?
A
Combines strength with resiliency
24
Q
What do adhesive glycoproteins do?
A
Help bind cells to ECM
25
What are the two ways cartilage can grow?
Appositional or Interstitial
26
What is Appositional growth?
Growth on surface, chondrogenic cells differentiate into chondroblasts (secrete ECM)
NEED perichondrium
27
What is interstitial growth?
Growth from within
| Chondrocytes mitosis/ECM secretion
28
What limits cartilage growth?
Avascular, can't grow beyond capability of diffusion
29
What are the downsides of cartilage?
Size limited and poor regenerative capacity
30
What limit s cartilage repair?
avascular and chondrocyte immobility
31
What can limited repair be intiated by?
Perichondrium
32
What occurs with cartilage repair?
Scarring = dense CT
33
Where is hyaline cartilage found?
Nose, articular cart., larynx, costal cart., etc
34
What is the function of hyaline cartilage?
Structural support (resist compression), bone growth, and repair
35
How does hyaline cartilage aid in bone growth?
Long bone template and growth plates
36
What type of growth occurs with hyaline cartilage?
Appositional and interstitial
37
What hyaline cartilage doesn't have perichondrium?
Articular and Epiphyseal growth plates
38
In what state are chondrocytes in hyaline cartilage?
Isogenous groups
39
What are the matrixes in hyaline cartilage?
Capsular, territorial, and interterritorial
40
What is in the capsular matrix?
Many PG's (very dark staining)
41
Where is the capsular matrix?
around chondrocytes
42
Where is the territorial matrix?
near chondrocytes
43
What is in the territorial matrix?
Type II fibrils and PG's (dark staining)
44
Where is the interterritorial matrix?
Away from chondrocytes
45
What is in the interterritorial matrix?
very few PG's (light staining)
46
Where is elastic cartilage found?
External ear, external auditory meatus, auditory tube, epiglottis, and larynx
47
What is the function of elastic cartilage?
Flexible structural support
| Has resiliency but is pliable
48
Is there perichondrium in elastic cartilage?
yes
49
What is the structure of the chondrocyte in elastic cartilage?
Abundant, isogenous groups present
50
What makes up the ECM in elastic cartilage?
Type II collagen, elastic fibers, and PG's
51
Where is fibrocartilage found?
Ligament insertions and w/i some joints
52
What is the function of fibrocartilage?
Rigid structural support, resists tension and compression (very tough)
53
Why is hyaline a transitional tissue?
combines features of hyaline cartilage and dense CT
54
Does hyaline have a perichondrium?
No
55
What is the structure of chondrocytes in hyaline cartilage?
Isogenous groups lined up with type I collagen
56
What does the ECM of fibrocartilage contain?
type I and II collagen w/ less ground substance
57
How is bone a specialized CT?
bones cells and mineralized ECM
58
What does bone contribute to the body?
framework, hematopoiesis, lever for muscles, and reservoir for minerals
59
What is the periosteum?
Contains the blood supply for the bone
60
What specialized structure is within the periosteum?
Sharpey's fibers
61
What are sharpey's fibers made out of?
type 1 collagen
62
What do Sharpey's fibers do?
adhere periosteum firmly to bone (tendon/ligament to bone)
63
What is the endosteum?
Monolayer of stem cells on internal surface of marrow cavity
64
What are the two portions of the bone ECM?
organic and inorganic
65
What makes up the organic portion of the bone ECM?
Mostly type I collagen and ground substance
66
What is ground substance?
PG's and glycoproteins
67
What does the organic portion of bone ECM give the bone?
flexibility and tensile strength
68
What makes up the inorganic portion of bone ECM?
Hydroxypatite crystals w/ type I collagen fibers
69
What does the inorganic portion of bone provide to the bone?
rigidity and compressive strength
70
What are the types of bone cells?
Osteocytes, osteoclasts, and osteoblasts
71
What are osteoblasts?
Bone forming cells
72
What does osteoblast organelle profile say about it?
extensive rER and golgi - makes ECM
73
What is an osteoid?
initial organic component
74
What makes the osteoid?
Osteoblasts
75
What happens to the osteoid?
calcified later on in development
76
What can effect the processing of the osteoid?
low in vitamin D
77
Where does an osteocyte come from?
Osteoblast
78
Where are osteoblasts located?
lacunea
79
What is different about osteoblast growth?
Amitotic
80
What is osteoblast's job?
maintain the ECM
81
Why do osteoblast's have long cytoplasmic processes?
mechanosensitive
82
Where do osteoclasts come from?
Monocytes
83
Where are osteoclasts?
in resorption bays (Howship's lacunae)
84
What is a ruffled border? What cell does this describe?
Osteoclast. Portion in direct contact with bone cause infolding of the plasma membrane
85
What is the function of an osteoclast?
Resorption of bone
86
What organelles do osteoclasts have more of due to it's function?
lysosomes, mitochondria, and increased surface area
87
What is the clear zone?
ring of cytoplasm around resorptive compartment
88
What purpose does the clear zone have?
prevent damage to surrounding tissues
89
What hormones affect bone?
PTH and calcitonin
90
Where does PTH come from?
Parathyroid gland
91
What does PTH promote?
resorption, leads to an increase in bone calcium levels
92
How does PTH affect bone?
receptors located on osteoblasts, lead to production of osteoblast stim. factor
93
What is the end result of PTH?
osteoclast stimulation
94
Where does calcitonin come from?
Thyroid gland
95
How does calcitonin affect bone?
Receptors on osteoclasts
96
What does calcitonin do?
inhibit osteoblast
97
What are the processes in bone remodeling?
resorption and formation
98
What regulates bone remodeling?
hormones and mechanically
99
What occurs with too much resorption?
osteopenia and osteoporosis
100
What occurs with too much formation?
osteosclerosis and osteopetrosis
101
What are macroscopic bone structure?
compact and trabecular bone
102
What is compact bone?
Cortical, dense
103
What is trabecular bone?
Cancellous, spongy (marrow)
104
Where is trabecular bone oriented?
toward stress lines
105
What are microscopic bone structures?
woven (immature) and lamellar (mature)
106
When is woven bone present?
initial bone formation and fracture repair
107
What is the cellular component of woven bone?
Poorly organized type I collagen, weak
108
What happens to woven bone?
replaced by lamellar bone
109
What is the cellular component of lamellar bone?
very strong, well-organized type-1 collagen
110
At what points does lamellar bone replace woven bone?
Primary and secondary bone formation
111
What is primary bone formation?
Primary osteons
112
What is secondary bone formation?
remodeling of primary bone
113
What are cement lines?
outer border of osteon, where bones tend to fracture
114
What is another name for osteons?
Haversian system
115
What is an osteon?
basic unit of bone, rings of lamellar bone around central canal
116
What is within the central canal?
blood vessels and nerves, diffusion through canaliculi
117
What is a perforating canal?
connect central canals with each other
| connect blood vessels in periosteum to marrow
