Lecture 2/3 - Bone and Cartilage Flashcards Preview

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Flashcards in Lecture 2/3 - Bone and Cartilage Deck (117):
1

What is the characteristic of the CT cartilage?

Specialized w/ abundance of ECM

2

What is the composition of ECM in cartilage?

Firm, w/ GAG's, proteoglycans, and collagen fibers

3

Why is the ECM of cartilage firm?

Bears a lot of mechanical stress

4

What do PG's interact with?

the collagen fibers

5

What are the three type of cartilages?

Hyaline, Elastic, and Fibrocartilage

6

What kind of blood support does cartilage have?

Avasular, relies heavily on CT for diffusion

7

What is missing (2 things) from cartilage?

Lymphatics and innervation

8

What are present in lacunae?

Chondrocytes

9

What do chondrocytes do?

secrete ECM

10

What are the layers of the perichondrium?

Outer fibrous layer and inner cellular layer

11

What are the characteristics of the fibrous layer?

Dense CT, collagen, fibroblasts, and avascular

12

What type of collage is in the fibrous layer?

Type 1 collagen

13

What is the perichondrium?

CT surrounding elastic and SOME hyaline cartilage

14

What is present within the cellular layer?

Chondrogenic cells

15

What are chondrogenic cells?

cartilage stem cells

16

Why is the perichondrium important?

appositional growth, maintenance, and some repair

17

What can chondrocytes form?

Isogenous groups since they are mitotic

18

What cells secrete ECM in cartilage?

Chondrocytes and chondroblasts

19

What type of collagen do ALL cartilage types contain?

Type II

20

What other collagen type does fibrocartilage have?

Type I collagen

21

What other collagen type does elastic cartilage have?

elastic

22

What do PG's do?

Shock absorbers, resist compression

23

Why is it beneficial that they interact with Type II fibers?

Combines strength with resiliency

24

What do adhesive glycoproteins do?

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