Basic Science Flashcards
1
Q
Factors that direct mesenchymal stem cells into osteoblasts
A
RUNX2, BMP
2
Q
osteoblasts form bone under _ strain and _ oxygen tension
A
low, high
3
Q
osteoblasts form cartilage under _ strain and _ oxygen tension
A
intermediate, low
4
Q
osteoblasts form fibrous tissue under _ strain and _ oxygen tension
A
high, low
5
Q
PTH effect on bone
A
Stimulates osteoblasts to form bone if pulsed, inhibits if constant
6
Q
1,25 Vit D effect on bone
A
stimulates osteoclasts through RANKL to resorb bone
7
Q
Calcitonin effect on bone
A
inhibits osteoclasts to resorb bone
8
Q
RANKL is produced by _ and activates _
A
osteoblast, osteoclast
9
Q
TNF-alpha function
A
inhibits osteoblasts
10
Q
Wnt function
A
stimulates osteoblasts
11
Q
Sclerostin is formed by _ and inhibits _
A
mature osteocytes, osteoblasts
12
Q
Sclerostin is released in response to _, and decreased under _.
A
Low stress concentration, high stress concentration
13
Q
Osteoclasts are derived from _.
A
Myeloid origin (hematopoietic) in macrophage lineage
14
Q
_ (native hormone) binds RANKL to inhibit signalling
A
Osteoprotegerin
15
Q
_ (pharmacologic agent) binds RANKL to inhibit signalling
A
Denosumab
16
Q
Bone resorption occurs in this part of osteoclast
A
how ship lacunae where the matrix is acidified and destroyed
17
Q
IL-1 _ osteoclasts
A
activates
18
Q
IL-10 _ osteoclasts
A
inhibits
19
Q
Most abundant non collagen protein in bone
A
Osteocalcin
20
Q
Lysomal enzyme in osteoclasts that resorb bone
A
Cathepsin K
21
Q
In bone provides tensile strength
A
collagen I
22
Q
In bone provides compressive strength
A
calcium hydroxyapetite
23
Q
Nutrient arteries supply the _ of bone
A
inner 2/3
24
Q
Periosteal capillary arteries supply _ of bone
A
outer 1/3
25
Type of bone formation during distraction osteogenesis
intramembranous
26
Fracture callus is _ bone formationo
enchondral
27
Deficiency of this enzyme inhibits bone formation in Howship lacunae
Carbonic anhydrase
28
Physical cellular zones from epiphysis to diaphysis
reserve zone, proliferative zone, hypertrophic zone, Zone of provisional calcification
29
Achondroplasia affects this part of physis
proliferative zone
30
Growth hormone affects this part of physis
proliferative zone
31
This zone of physis widens in rickets
hypertrophic zone due to insufficient calcification
32
SCFE occurs through which zone?
Hypertrophic
33
SCFE in renal osteogenesis occurs in what zone?
metaphysis
34
B- cantenin increases _ osteoblast activity
increases
35
SOX9 controls _
chondrocyte production
36
PTH effect on sclerostin
Increase sclerostin (decreases osteoblast activity)
37
Calcitonin effect on sclerostin
Decreases sclerostin (increases osteoblast activity); calcitonin also decreases osteoclast activity to decrease bone resorption
38
tartrate resistant acid phosphate does what and is produced by what enzyme?
Acidifies bone matrix in howship lacunae; formed by carbonic anhydrase
39
Osteopetrosis is caused by a defect in _, thereby _.
carbonic anhydrase, decreasing bone resorption
40
Groove of Ranvier and Ring of Lacroix contribute to _.
Width growth at the physis
41
Enchondral bone formation _ involve a cartilage phase
does
42
intramembranous bone formation _ involve a cartilage phase
does not, formed directly from MSCs that differentiate into osteoblasts
43
In soft callus what type of collagen forms first?
Type II
44
BMP-2 is indicated for treatment in _
Acute open tibia fractures
45
BMP-7 is indicated in _
tibia non unions
46
Role of Cox-2 in bone?
Required for normal enchondral ossification
47
Effect of low intensity pulse ultrasound?
strengthens callus
48
Quinolone antibiotics effect on bone?
toxic to chondrocytes, inhibit fracture healing
49
TGF-B effect on osteoblasts
stimulates osteoblast to produce collagen, found in fracture hematomas
50
Highest compressive strength of any graft material
Calcium phosphate cement
51
Calcium sulfate cements are associated with _
wound drainage
52
Centigrays of radiation to prevent HO
600-800
53
Primary regulators of serum calcium
PTH and 1,25 VitD3
54
Cartilage in soft callus is degraded by _
MMP-13 secreted by chondrocytes
55
Systemic effect of PTH
increased Ca, Decreased Phosphate
56
Systemic effect of Calcitonin
Decreases calcium (no effect on phosphate)
57
Active form of Vit D
1,25 Vit D
58
Form of Vit D measured in serum tests
25 Vit D
59
liver does what conversion to Vit D
Vit D -> 25 Vit D
60
Effect of 1,25 Vit D
Increases intestinal absorption of Ca, Phosphate. Stimulates Osteoclasts via RANKL through osteblast binding
61
Where is PTH produced?
Chief cells of parathyroid
62
Where is 1,25 Vit D produced
proximal tubule of kidney
63
Where is calcitonin produced?
parafollicular cells of thyroid
64
What stimulates PTH production?
low serum Ca
65
What stimulates calcitonin production
high serum Ca
66
What stimulates 1,25 Vit D production?
PTH
67
Effect of PTH on kidney
Increased Ca resorption, increased phosphate excretion, 1,25VitD production; Net increase Ca, decrease Phosphate
68
Metabolic findings of hyperparathyroidism
high Ca, low Phosphate
69
Renal Osteodysphtrophy causes _ (2)
decreased 1,25 Vit D production, decreased Phosphate excretion
70
Overall effect of rickets
widening of physis through zone of provisional calcification and thin cortexes with bowing
71
```
Serum findings of nutritional rickets:
Ca
PTH
Phosphate
Alk Phos
25Vit D
1,25VitD
```
Ca: low to normal (decreased Intestinal absorption)
PTH: High (due to decreased intestinal Ca absorption)
Phosphate: Low (Increased kidney excretion from high PTH)
Alk Phos: High (from bone turnover of PTH)
25Vit D: low
1,25VitD: low
72
```
Serum findings of Ca deficient rickets:
Ca
PTH
Phosphate
Alk Phos
25Vit D
1,25VitD
```
Ca: decreased or normal
PTH: Increased (due to decreased Ca absorption)
Phosphate: decreased (due to high PTH)
Alk Phos: increased (due to high bone turnover)
25Vit D: normal
1,25VitD: high
73
Type 1 Hereditary Vit D Dependent Rickets is defect in _?
1alpha 25VitD hydroxylase that makes active VitD
74
Treatment for Vit D Dependent Rickets?
Oral 1,25VitD (Calcitrol)
75
Most common form of rickets
Familial hypophosphatemic rickets
76
```
Serum findings of familial hypophos rickets:
Ca
PTH
Phosphate
Alk Phos
25Vit D
1,25VitD
```
```
Ca: normal
PTH: Normal
Phosphate: decreased
Alk Phos:
25Vit D
1,25VitD
```
77
Cause of familial hypophos rickets
Impaired renal tubular resorption and Vit D response
78
Type 2 Hereditary Vit D Dependent Rickets is defect in _?
intracellular Vit D receptor
79
Treatment for Hereditary Vit D Dependent Rickets is?
Burosmab (anti FGF 23 antibody), Phosphate
80
Osteoporosis Z score is
less than -2.5
81
Osteopenia Z score is
-1 - -2.5
82
Effect of Bisphosphanates
Direct inhibition of osteoclasts, prevents formation of ruffled border (where bone resorption happens), and causes apoptosis
83
Nitrogen containing bisphosphonates are _ times more potent than non nitrogen containing
1000
84
Specific risk of bisphosphonate therapy
AVN of jaw
85
Scurvy has what effect on the physis
widening of zone of provisional calcification
86
Paget disease is characterized by
abnormal osteoclast function with virus like inclusions in the cell
87
Clonazepam _ sclerostin
increases (thereby decreasing bone production)
88
Teriparatide is called _ and is a synthetic analog of _
Forteo; PTH
89
Contraindications to the use of Forteo (2)
Paget's dz, previous history of bone mets
90
Myasthenia Gravis is a caused by?
IgG antibody to ACH receptor
91
Type I muscle fibers are:
Slow twitch, oxidative, red; high triglyceride content
92
Type I fibers are increased in _ activities
endurance
93
Type II fibers are
fast twitch, glycolytic, "white"
94
Type II fibers are increased in _ activities
high intensity, short duration
95
Immobilization causes what effect on muscle healing
atrophy
96
TGF-B has what effect on muscle healing?
stimulates myofibroblasts, increases fibrosis
97
What is Decorin?
proteoglycan in tendons that links adjacent collagen molecules, regulates tendon diameter, decreases TGF-B effect
98
First type of Collagen formed in tendon healing?
Type III
99
Order of nerve layers:
Axon, myelin sheath, endoneurium, fascicles, perineurium, epineurium
100
Neuropraxia is caused by:
local conduction block caused by ischemia, selective demyelination; reversible
101
Axonotemesis
Disruption of myelin sheath, epineurium intact, Mullerian degeneration distally
102
Neurotemesis
Complete nerve transection; Mullerian degeneration distally
103
4 zones for tendon to bone connection
Tendon, fibrocartilage, Sharpey's mineralized fibrocartilage, Bone
104
Tendon healing weakest at what point
7-10 days after repair
