5.3 lect - cartilage, bone, synovial joint Flashcards Preview

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Flashcards in 5.3 lect - cartilage, bone, synovial joint Deck (113)
1

which is the "apical" side of an osteoblast?

faces the osteoid

2

the apical side of this bone cell is thrown into folds to increase surface area

osteoblast (secreting osteoid)
osteoclast has ruffle border (H+ pumps)

3

what are the 3 specialized regions of an osteoclast?

-ruffle border (incrased surface area for H+ pumps into howship lacuna)
-sealed clear zone (actin filaments & adhesion proteins seal off active resorbing area)
-basolateral region (exocytosis of digested vesicles to enter capillaries and systemic circulation)

4

what is hyaline cartilage

a hydrated matrix of type II collagen with entrapped chondrocytes

5

while chondrocytes are found at the center of a hyaline cartilage tissue, these cells are found on the periphery

chondroblasts

6

chondrocytes that divide after being entrapped form ...

isogenous groups

7

the cartilage matrix can be divided by staining properties into __ and __

-territorial matrix (rich in GAGs) near chondrocytes
-interterritorial matrix away from chondrocytes

8

the dense connective tissue layer surrounding hyaline cartilage is called

perichondrium

9

this tissue type is usually found where dense connective tissue inserts into cartilage

fibrocartilage

10

what is contained within canaliculi?

processes of osteocytes

11

this cell functions to secrete osteoid, pre-mineralized bone matrix

osteoblasts

12

a quiescent osteoblast is a...

bone lining cell

13

5 resident cells of bone

osteoprogenitor
osteoblast
bone lining
osteocyte
osteoclast

14

this cell is responsible for resorption of bone

osteoclast

15

how is an inactive osteoclast morphologically different from an active osteoclast?

inactive - mononucleated (monocyte)
active - large multinucleated (fusion of monocytes)

16

how does an osteoclast resorb bone?

creates a sealed space, howship's lacuna, into which H+ ions and enzymes are pumped across the ruffled border

17

creates a sealed space, howship's lacuna, into which H+ ions and enzymes are pumped across the ruffled border

osteoclast

18

together, __, __, and __ surround the surfaces of mineralized bone

osteoblasts
osteoclasts
bone lining cells
(perhaps morphologically indistinguishable osteoprogenitor cells)

19

T/F osteoprogenitor cells give rise to osteoclasts

false
monocytes do

20

osteoprogenitor cells give rise to...

osteoblasts
osteocytes
bone lining cells

21

__ bone comes about through remodeling

lamellar (secondary) bone

22

__ bone is newly formed

woven (primary) bone

23

how is a haversian canal formed?

-cutting cone of osteoclasts
-closing cone of osteoblasts
(tunneling along axis of maximal stress)

24

cutting cone

cone of osteoclasts tunneling along axis of maximal stress to make room for a new osteon

25

closing cone

cone of osteoblasts filling tunnel created by cutting cone of osteoclasts along axis of maximal stress to make new osteon

26

what ensures patency of the bone's blood supply?

volkmann's canals growing across lamellae to join haversian canals

27

what is an "anastomosing network"

linking of streams
e.g. volkmann's canals connect haversian canals to creat an anastomosing network of vessels

28

T/F bone is a static structure

false
dynamic structure, constantly remodeling

29

where is cartilage present on ribs?

ventrally at connections to sternum

30

this tissue functions in:
-structure with flexibility
-structure in the context of intermittent forces (joints, respiratory system)
-shock absorption
-fast growth

cartilage

31

this tissue functions in:
-withstanding compressive and tensile forces
-levers for movement
-protection of organs
-calcium storage

bone

32

cells dispersed in an ECM =

connective tissue

33

cells of this connective tissue are not especially important to funciton

cartilage

34

"hylos" =

greek for glassy

35

hyaline cartilage matrix is composed of...

70% water
collagen
ground substance
glycoproteins (e.g. fibronectin)
proteoglycans

36

what is the predominant material in cartilage?

water
70%

37

why are there large vacuoles in cartilage on LM?

fixation artifact

38

T/F cartilage is avascular

true

39

this ECM component has a "bottle brush" appearance

proteoglycan aggregates
-glycoscylations stemming / radiating out from hyaluronic acid core

40

what is a proteoglycan in the ECM?

glycoscylations stemming / radiating out from hyaluronic acid core

41

aggrecan

one type of proteoglycan aggregate
-glycoscylations stemming / radiating out from hyaluronic acid core

42

glycoscylations stemming / radiating out from hyaluronic acid core

proteoglycan aggregate

43

proteoglycans bind...

water and collagen

44

proteoglycans have a net __ charge

negative

45

how are nutrients transported to chondrocytes?

via hydrated ECM of proteoglycan aggregates and water
through compressive forces

46

is territorial matrix more eosinophilic or more basophilic? why?

basophilic
more GAGs (which are negative)

47

surrounds isogenous groups in hyalin cartilage

territorial matrix

48

between isogenous groups in hyalin cartilage

interterritorial matrix

49

what kind of cartilage is found in the trachea and lung airways?

hyaline cartilage

50

eustation tube
epiglottis
external ear
are made up of...

elastic cartilage

51

the epiglottis is made of...

elastic cartilage

52

cartilage with thin dark staining fibers in the matrix is probably...

elastic cartilage

53

what kind of cartilage in intervertebral disks?

fibrocatilage
(surrounding juicy nucleus pulposus)

54

herniated disk

fibrocartilage in intervertebral disk tears and juicy nucleus pulposus leaks out

55

how to distinguish chondrocytes from fibroblasts in fibrocartilage?

round cells - chondrocytes
fusiform cells - fibroblasts

56

synovial fluid consists of...

water (transudate from capillary plexus)
proteoglycans
hyaluronic acid
(secreted by B-cell synoviocytes)

57

2 layers of synovial membrane

-intimal layer (1-4 layers of synoviocytes)
-subintimal layer (fibrovascular)
*both encompassed within joint capsule*

58

intimal layer of synovial membrane

1-4 layers of synoviocytes
A-cells (macrophages)
B-cells (synovial fluid secretion)

59

T/F synovial fluid consists of a mixture of transudate from capillary plexus and ground substance

true

60

subintimal layer of synovial membrane

fibrovascular layer between intima and joint capsule

61

T/F cartilage has a highly limited capacity for repair

true
avascular

62

T/F cells in the perichondrium have the capacity to differentiate into chondrocytes to aid cartilage repair

true
but this capacity is limited

63

cartilage repair

-cells in perichondrium have limited capacity to differentiate into chondrocytes
-defects are often filled by fibroblasts, which produce dense scar limiting and impairing recovery of function

64

T/F any trauma to cartilage (over-training, surgery, etc) does not repair well and will probably scar

true

65

fibronectin

a glycoprotein found in round substances of connective tissues

66

what substance is exclusively found in cartilage?
-type I collagen
-fibronectin
-type II collagen
-heparin

type II collagen

67

what are the consequences of the avascular an non-innervated nature of catilage

-lower chance of transplant rejection
-poor recovery after damage
-no direct pain from damage
-diffusion from surrounding ct must supply metabolic support

68

T/F cartilage has a relatively lower chance of transplant rejection

true
avascular and non-innervated

69

T/F no direct pain is felt from cartilage damage

true
avascular and non-innervated

70

T/F diffusion from surrounding connective tissue supplies metabolic support to chonrocytes

true
avascular and non-innervated

71

where does bone marrow exist?

between trabeculae of spongy cancellous trabecular bone

72

this type of bone is highly organized to confer strength without increasing weight (e.g. like the eiffel tower)

trabecular spongy cancellous bone

73

this type of bone is a three-dimensional latticework that uses arches, rods, and plates to counter forces and provide maximum support for weight

trabecular spongy cancellous bone

74

3 main parts of compact bone

outer circumferential lamellae
inner circumferential lamellae
osteons (haversian systems)

75

T/F circumferential lamellae refer to osteons

false
surround entire inside or outside of bone

76

T/F osteons usually run perpendicular to the long axis of the bone

false
usually run parallel to long axis of bone

77

how are adjacent lamella of an osteon oriented to one another?

90 degree angles (opposite twisting slants)
-reason for appearance in polarizing microscope

78

what are the lamellae of the osteon?

10% water
45% organic material (mostly type I collagen, some ground components)
45% mineral (hydroxyapatite crystals Ca10(PO4)6(OH)2 )

79

what is the organic material of bone?

mostly type I collagen
some ground components
-osteonectin (binds mineral to collagen I)
-osteopontin (binds cells to matrix)

80

what is the ground substance in bone?

-osteonectin (binds mineral to collagen I)
-osteopontin (binds cells to matrix)

81

what is bone mineral?

hydroxyapatite crystals
Ca10(PO4)6(OH)2

82

what is hydroxyapatite?

Ca10(PO4)6(OH)2
bone mineral

83

what is the collagen type in bone?

type I

84

how is bone mineralized?

hydroxyapetite is deposited inside type I collagen fibers, between fibrils

85

osteogenesis imperfecta

bone deprived of type I collagen elements, minerals are more brittle, bones broken more easily

86

T/F osteoblasts are interconnected by gap junctions

true

87

on EM, a cell with prominent golgi apparati beside a layer of collagen beside a layer of very dark black probably depicts...

an osteoblast next to an osteoid layer next to a mineralized bone matrix

88

T/F canaliculi are the osteocyte processes that communicate with one another in tiny canals across osteon lamellae

false
canaliculi are the actual tunnels, not the osteocyte processes within them

89

how are osteocyte processes linked to one another?

gap junctions

90

what is one function of an osteocyte?

sense forces through the filaments connecting it to bone

91

how do bone lining cells connect to each other?

gap junctions

92

T/F gap junctions connect both bone lining cells and osteoblasts to one another

true

93

T/F you will be asked to identify osteoprogenitor cells

false
too similar morphologically to bone lining cells

94

where are osteoprogenitor cells present?

inner cellular periosteum
endosteum
lining haversian canals

95

where do osteoprogenitor cells come from?

mesenchymal stem cells

96

osteoclasts regulate ...

calcium homeostasis

97

how do osteoclasts regulate calcium homeostasis?

low serum calcium
-thryoid secretes parathyroid horomone to inhibit osteoblasts
-osteoblasts release osteoclast stimulating factor (RANKL) to activate osteoclasts

high serum calcium
-thyroid secretes calcitonin to inhibit osteoclasts

98

how does the thyroid gland regulate calcium homeostasis?

-parathyroid hormone inhibits osteoblasts and stimulates them to release RANKL to activate osteoclasts
-calcitonin inhibits osteoclasts

99

what gland is key in regulating calcium homeostasis

thyroid gland
-parathyroid hormone inhibits osteoblasts and stimulates them to release RANKL to activate osteoclasts
-calcitonin inhibits osteoclasts

100

how does parathyroid hormone affect bone?

inhibits osteoclasts and stimulates them to release RANKL to activate osteoclasts
-increase serum calcium concentrations
-released by parathyroid gland

101

how does calcitonin affect bone?

inhibits osteoclasts
-decreases serum calcium levels
-released by thyroid gland

102

RANKL

osteoclast stimulating factor
-released by osteoblasts in response to parathyroid parathyroid hormone

103

what is the process by which the transition from woven immature bone to lamellar mature bone accomplished?

bone remodeling

104

bone remodeling

what is the process by which the transition from woven immature bone to lamellar mature bone accomplished

105

describe bone remodeling in 3 steps

-cutting cone of osteoclasts
-vascularization
-closing cone of osteoblasts

106

what happens to osteoblasts in the closing cone during bone remodeling?

become trapped osteocytes or bone lining cells along haversian canal

107

what is the name of the structure created by a cutting cone of osteoclasts

resorption tunnel

108

T/F bone remodeling ceases when all woven immature bone has been converted to lamellar mature bone

false
remodeling continues to respond to stressors, creating new osteons and revising structure

109

type X collagen

short chain collagen expressed by hypertrophic chondrocytes during endochondral ossification at the growth plate

110

short chain connective tissue fibers expressed by hypertrophic chondrocytes during endochondral ossification at the growth plate

type X collagen

111

how can you differentiate between an osteoblast and an osteoclast on EM?

-osteoblast: folds are not as apparent, collagen fibers in osteoid unmineralized matrix
-osteoclast: ruffled border is Very apparent, no apparent collagen fibers in demineralized matrix

112

T/F gogli aparati are apparent in EM of osteoblast but not of osteoclast

false
-osteoblast secretes osteoid and vesicles for calcification
-osteoclast repackages endocytosed vesicles for basolateral release for eventual reuptake into plasma

113

how to tell difference between osteoblast and osteocyte on EM?

-osteocyte will be completely surrounded by mineralized matrix, osteoblast will only have apical mineralized matrix
(both may have a layer of unmineralized matrix - apically for osteoblast, in lacuna for osteocyte)