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Flashcards in Bones 1 Deck (86):
1

what are the 3 types of cell in bone ? how many nuclei? basic multicellular unit

osteoclasts ( multiple_
osteoblasts (single nucleus)
osteocytes

2

RANKL located on what cell

osteoblasts and marrow stroma cells

3

RANK is located on what cell? role?

osteoclast precursor
- allow OC generation and survival

4

explain the M-CSF pathway

1. M-CSF secreted by OB
2. M-CSF binds to OC: generation and survival

5

explain the WNT/Beta-catenin pathway

1. WNT from marrow stromal cell
2. LRP5 and LRP6 OB receptor bind WNT protein
3. OB secretes OPG ( blocks RANK)

6

bone compositition

calcium hydroxyapatite
organic matrix with type I collagen

7

what are the two types of bone? where are they found

woven bone: random collagen
lammellar bone: ordered collagen
compact bone
spongy bone

8

name two bone enzymes

osteopontin
alkaline phosphatase

9

role of osteopontin ( osteocalcin)

levels parallel osteblast activity

10

alkaline phosphatase comes from what organ

osteoblasts
liver and placenta

11

woven bone?
how fast does it grow?
forces?

rapid bone growth
resists forces in all directions
pathologic in adults

12

lamellar bone replaces what

woven bone
stronger than woven bone

13

what process forms bone?

intramembranous ossification
- direct from mesenchyme
- appositional growth

14

location of epiphysis

distal to growth plate

15

location of metaphysis

beneath growth plate

16

location of diaphysis

center

17

Dysostosis

local problems in migration of mesenchyme and their condensation

18

dysplasia

global defect in regulation of skeletal organogenesis

19

Cleidocarnial dysplasia
-inherited
-defect protein

autosomal dominant
-RUNX2 (CBFA1)

20

clincial presentation for Cleidocranial dysplasia

short
abnormal clavicle
supernumery theeth
wormian bone ( extra sutural bone)

21

what goes wrong in achondroplasia

-growth plate defect from paracrine cell defect
-reduced chondrocyte proliferation in growth plate

22

achondroplasia is a defect in what gene? what does it cause

FGFR3 point mutation
-inhibits cartilage growth

23

how is achondroplasia passed on to generations

paternal allele
autosomal dominant

24

what growth is still present for achondroplasia? what does this cause

appositional and intramembranous bone formation
-thick cortical bone

25

clinically what does achondroplasia look like

short proximal limbs
normal turnk
enlarged head
depression of root nose
normal reproductive and intelligence

26

what is the most common lethal dwarfism

Thanatophoric dwarfism

27

thanatrophoric dwarfism is a mutation in what

FGFR3

28

clinical presentation of thanatophoric dwarfism

cloverleaf leaf
bell-shaped abdomen

29

LRP5 is a receptor that activates what

WNT/beta-catenin in OB
- produces OPG (Blocks RANKL)

30

what disease has an inactive LRP5

osteoporosis pseudoglioma syndrome
- skeletal fragility
- loss of vision

31

Marble bone disease

osteopetrosis

32

what goes wrong in osteopetrosis

reduced osteoclast bone resorption
- cannot acidify pit
- defect in RANKL
LRP5 gain of function

33

in osteopetrosis bone deposition replaces what

medullary cavity
- no room for hematopoiesis

34

what does osteopetrosis look like on X-ray

Erlenmeyer flask

35

how is osteopetrosis passed down

autosomal dominant

36

brittle bone disease

osteogenisis imperfecta

37

Osteogensis imperfecta what goes wrong

type 1 collagen disease
- mutation of alpha 1 and 2 chains
extreme skeletal fragility

38

what is the most common type of autosomal dominant bone disease

osteogenisis imperfecta

39

clinical features of Autosomal dominant osteogensis imperfecta

blue sclera
hearing loss
dentin defect

40

Type 2, 9, 10, 11 collagen disease has a defect in what?

hyaline cartilage
-

41

Mucopolysaccharidoses is a defect in what

enzymes degrading dermatan sulfate, heparan sulfate, keratan sulfate
- abnormal hyaline cartilage
- malformed bone

42

what is osteoporosis

increase bone porosity
decrease mall

43

primary osteoporosis

senile, postmenopausal

44

secondary osteoporosis

drugs, diabetes,

45

compare osteoporosis and osteopenia

osteopenia: decrease bone mass
osteoporosis: osteopenia to point of risk of fracture

46

senile osteoporosis what happens to the osteoblasts? cortex?

reduce metabolism
cortex is thinned

47

when is skeletal mass peak for senile osteoporosis

young adult

48

in postmenopausal osteoporosis what happens when estrogen is decreaed

increase inflammatory cytokines
increase RANKL
decrease OPG
OC>OB

49

rickets

child vitamin D deficiency

50

osteomalacia

adult vitamin D deficiency

51

renal osterodystrophy

chronic renal disease
- increase or decreased OC/OB activity
- decrease Vitamin D conversion

52

what happens to OC and OB in hyperparathyroidsim

more OC

53

what does the X-ray look like for hyperparathyroidsim

bone loss radial aspect of middle phalange of index and middle finger
-osteopenia

54

Paget disease involve what bone

axial skeleton
proximal femur

55

what are the 3 stages of paget disease

osteolytic stage
mixed stage
osteosclerotic stage

56

osteolytic stage

loss of bone mass

57

mixed stage

osteolytic and osteoblastic

58

osteosclerotic stage

jigsaw puzzle-like cement lines of lamellar bones

59

paget disease has an increase in what enzyme? what values stay the same

alkaline phosphatase
normal Ca and PO4

60

Paget disease: pain overgrowth can lead to

cranial nerve palsy
heavy skull

61

what happens to the skin in Paget disease

warm skin over affected bone with hypervasculatiry
-high-output cardiac failure

62

treatment for Paget disease

Calitonin and biphosphonates

63

bony callus

woven bone
-overtime can bear weight

64

Soft tissue callus

easily disrupted
hematoma fibrin
osteoprogentor cells activated

65

peak bone mass

early adulthood

66

how can a genetic factor cause osteoprosis

vit D receptor polymorphism

67

is an X-ray and serum levels of calcium, phosphorous, alkaline phosphate helpful in diagnosing osteoporosis

NO

68

osteitis fibrosa cystica

severe form of parathyroidsm

69

pseudoarthrosis

non union

70

osteonecrosis

infarction of bone marrow

71

most common cause of osteonecrosis

corticosteroid

72

in osteonecrosis what is dead bone/fat replaced by

Ca soaps

73

name 5 things that can cause avascular necrosis

corticosteroid
pregnancy
infection
dysbarism
sickle cell disease

74

subchondral infarct what doe sit look like

wedge-shaped subchondral bone

75

osteomyelitis

inflammation almost always from infection

76

how does bacteria reach bone

hematogenous
direct
implantation

77

X-ray for osteomyelitis

lytic bone lesion with surrounding sclerosis

78

most common bacteria in pyogenic osteomyelitis

s. aureus

79

most common bacteria in pyogenic osteomyelitis for infants

group B
H. influencza

80

where does pyogenic osteomyeltissi occur in bone in neonate
children
adult

neonate: metaphysis/epophysis
children: metaphysis
adult: epiphysis and subchondral bone

81

sequestrum

dead piece of bone

82

brodie abscess

small intraosseous abscess often in cortex walled off by reactive boone

83

involucrum

reactive surrounding bone

84

process of pyogenic osteomyelitis

sequestrum
chronic inflammation : brodie abcxess
involucrum

85

congential syphilis

at enchondral ossification centers and periosteum

86

acquired syphilis of bone? what type of bone and clinical presentsion

bone in tertiary phase
saddle nose, saber shin ( tibia)