Basic Science Flashcards
(153 cards)
1
Q
osteoblast derived from:
A
undifferentiated mesenchymal stem cells
2
Q
mesenchymal cells become osteoblasts under what factors
A
- low strain and increased O2 tension
- Transcription factors RUNX2
- BMP
- Core binding factor Alpha 1 and beta-Catenin
3
Q
Mesenchymal cells become cartilage under what conditions
A
Intermediate strain and low O2 tension
4
Q
pulsatile PTH
A
stimulate osteoblast ativity
5
Q
Osteoblasts secrete
A
Alk Phos RankL Type 1 Collagen Bone sialoprotein Osteocalcin (stim by Vit D)
6
Q
Osteoblasts inhibited by
A
TNF Alpha
7
Q
WNT’s causes
A
osteoblast proliferation and survival
=increased WNT=increased bone mass
8
Q
Molecules that sequester wnt
A
Sclerostin and Dickkopf
these inhibit wnt and cause dec bone mass
Inhibiting these will allow WNT to work and cause increased bone mass
9
Q
former osteoblasts surrounded by mature bone
A
osteocytes- from mesenchymal lineage
90% of cells in mature bone
control Ca and PO4 homeostasis
10
Q
PTH function
A
stimulates clast activity
activates adenylyl cyclase
11
Q
1,25 Vit D3 function on Blasts
A
increases matrix and alk phos synthesis, and production of bone specific proteins
12
Q
Glucocorticoid effect on blasts
A
inhibits DNA synthesis, collagen, and protein production
13
Q
prostglandins effect on blasts
A
stimulates bone resorption via activation of Adenylyl cyclase
14
Q
Estrogen on blasts
A
anabolic and anticatabolic
inhibits adenylyl cyclase
15
Q
calcitonin on CLASTS
A
inhibits clasts and dec bone resoprtion
16
Q
lineage of osteoclasts
A
hematopoietic stem cells of macrophage lineage
17
Q
mature osteoclasts bind surfaces by
A
integrin (AlphaVbeta3) or vitronectin receptor)
18
Q
howship lacunae mechanisms
A
seal space below clast make tartrate resistant acid phosphatase carbonic anyhydrase=hydrogen ions lower pH increase solubility of hydroxyapatite crystals
19
Q
Released by clasts after HA removed to degrade the organic matrix
A
cathepsin K-lysosomal enzyme
20
Q
IL1 and IL 10 function
A
IL 1= potent stimulator of clast differentiation and bone resoprtion
- inhibited by anakinra which inhibits clasts and resorption
- found in TJA osteolysis scenarios
IL 10= suppresses osteoclasts
21
Q
predominant collagen in bone
A
TYPE bONE collagen
provides the tensile strength
22
Q
Most abundant non collagen protein in bone
A
osteocalcin
*inhib by PTH
Measure of bone turnonver in urine
23
Q
60 % dry weight of bone is inorganics
Ca hydroxyapatite
A
Ca10(PO4)6(OH2)
24
Q
attracts osteoclasts, direct regulation of bone density
A
osteocalcin
25
secreted by platelets, regulates calcium and organizes matric
osteonectin
26
similar to an integrin and is a cell binding protein
osteopontin
27
Arterial flow in mature bone is in which direction
centrifugal- inside to out, which is the net effect of the high pressure nutrient artery haversian canal system and low pressure periosteal system
28
with fracture how does blood flow in the bone
with fx, the centrifugal system is disrupted, the low pressure periosteal system predominates and the flow is out to in centripetal
29
flow in immature bone
out to in, due to high vasc periosteum, ceintripetal
30
Venous flow in mature bone direction
out to in centripetal
31
Bone replaces a cartilage model
enchondral bone formation
LongBones
Fracture Callus
bone made with DBM
32
aggregate of undifferentiated mesenchymal cells differentiate into osteoblasts which form bone
intramembranous-
flat bones
Distraction osteogenesis
Blastema bone
33
osteoblasts lay down new bone on existing bone
appositional bone formation
bone formation phase of bone remodeling
Periosteal bone enlargement
34
Disorder of enchondral bone formation
achondroplasia
35
disorder of intramembranous bone formation
cleidocranial dysostosis
36
Disorder of appositional growth
paget's
melorheostosis
infantile hyperostosis Caffey Dz
37
when do bones begin to form in utero
6 weeks
38
primary ossification centers formed when at gestation
8 weeks
39
differentiation stimulated in part by binding of what to what
WNT binds to LRP5 and LRP6-
40
zones of enchondral bone formation
reserve zone
proliferative zone
hypertophic zone
metaphysis
41
Lysosomal storage dz causes dysfunction in what zone
reserve zone (gaucher's dz)
42
decreased O2 tension occurs in what zone
reserve zone
43
stores lipids glycogen and proteoglycans
reserve zone
44
achondroplasia affects which zone
proliferative zone
45
growth hormone acts on what zone
proliferative zone
46
in this zone, growth is longitudinal, with stacked chrondocytes, cell proliferation and matrix production, O2 tension increases and proteoglycans inhibit calcification
proliferative zone
47
SCFE affect what zone
hypertrophic zone
48
3 sub zones of hypertrophic zone
maturation
degeneration
provisional calcification
49
matrix mineralization occurs in
hypertrophic zone
50
PTHrP effect on chrondrocytes
inhibits chrondocyte maturation
51
IHH produced by chrondocytes and does what
regulated (dec) expression of PTHrP
Thus increases chondocytme maturation
and increases matrix mineralization/bone formation
52
which zone widens in Rickets with little to now provisional calcification
Hypertrophic Zone
53
diastrophic dwarfism zone
reserve- TYPE II collagen synthesis defect
54
psueoachondroplasia zone
reserve, defect in processing PG
55
Kneist syndrom zone
reserve, PG defect
56
Giganstism zone
proliferative zone- increased GH
57
achon zone
proliferative - FGFr23
58
malnutrition, irradtiation and steroid excess zone
proliferative- dec prolif or matrix synthesis
59
Mucopolysacharidoses affect what zone
maturationa and degeneration zones of hypertrophic zones- deficicnecy in lysosomal acid hydrolases and storage of mucopoly's- cells cannot prepare matrix for calcification properly
60
rickets and osteomalacia zone
zone of provisional calcification zone
61
acute hematogenous osteomyelitis
primary spongiosa of metaphysis-sluggis circulation and, reticuloendothelial deficiency, low PO2
62
osteopetrosis zone
Secondary spongiosa- abnormal clasts (cannot remodel internally)
63
function of secondary spongiosa
remodeling zone
64
scurvy zone
2ndary spongiosa-inadequate collagen formation
65
Osteogenesis imperfecta zone
2ndary Spongiosa abnormal blasts and collagen synthesis
66
metaphyseal displasia (Pyle dz) zone
secondary spiongiosa
67
SCFE zone in renal osteodystrophy
metaphyseal spongiosa
68
inheritence pattern for X linked Hypophosphatemic Rickets
X linked Dominant- one X allele hey have the trait,
69
branches of axillary artery
```
Screw the lawyer, save a patient!
S: superior thoracic artery
T: thoracoacromial artery
L: lateral thoracic artery
S: subscapular artery
A: anterior humeral circumflex artery
P: posterior humeral circumflex artery
```
70
study needed and tumor associated with Bekwith Wideman
```
need afp levels 3-4 times ayear until 8 yo
abdominal and pelvic usg
r/o wilms tumor
hemihypertrophy and large tongue
10% risk of wilms tumor
```
71
extensor compartments of wrist
```
1- EPL and APB
2. ECRL/ECRB
*Listers*
3. EPL
4, EDC, EIP
5, EDM
6 EDCU
```
72
What is an isotropic material
it has similar mechanical properties regardless of the orientation of the material. Examples of isotropic materials include metals, plastics, and methacrylate. Most biologic tissues are anisotropic, meaning their mechanical properties alter depending on the materials’ orientation to the applied stress.
73
spots for anatomic biopsy
| o Wrist
dorsal 2nd compartment
74
site for biopsy distal humerus
o Distal Humerus = lateral triceps, brachialis muscle
75
biopsy spot proximal humerus
o Proximal Humerus = anterior deltoid muscle
76
illiac biopsy spot
o Iliac = thru superior abductor muscles
77
supraceteabular region biopsy spot
o Supracetabular = Smith-Peterson approach through TFL and rectus femoris muscle
78
femoral neck and head biopsy spot
o Femoral Neck and Head = transtrochantlric osseous approach
79
distal femur biopsy spot
o Distal Femur = posteromedial or posterolateral border of vastus medialis/lateralis muscle
80
tibia biopsy spot
o Tibia = subcutaneous border of tibia
81
patellar problem when converting HTO to total knee arthroplasty
patella baja
82
o Tibia = subcutaneous border of tibia
bone placed in longitudinal tension will tend to stimulate longitudinal growth, and that compressive longitudinal forces inhibit longitudinal growth
(think Dr. Dan's thethering proecuderes0
83
Wolff's law
bone remodels in response to mechanical stress, with the correlate that increased stress causes increased growth, and decreased stress leads to bone loss.
84
bone remodels in response to mechanical stress, with the correlate that increased stress causes increased growth, and decreased stress leads to bone loss.
affects bacterial protein synthesis through a unique inhibition of the bacterial ribosome. Linezolid binds to a site on the 23S ribosomal RNA of the 50S subunit, preventing formation of the 70S initiation complex and interrupting the translational process
85
penicillin abx inhibit what
bacterial cell wall synthesis
86
florquinonlones MOA
-cipro- DNA gyrase
87
rifampin MOA
DNA-dependent RNA polymerase is inhibited
88
Bacterial cell membrane depolarization interrupting DNA, RNA, and protein synthesis is the mechanism of action of
Daptomycin
89
glucagon is catabolic or anabolic in skeletal muscle
catabolic-hormone of starvation-mobilized stored energy
90
insulin is catabolic or anabolic in skeletal muscle
anabolic-hormone of plenty
91
lactate level for DCO
should be less than 2.5, if greater then consider DCO
92
fibrinogen level for DCO
should be greater than one, if less consider DCO
93
base deficit for DCO
should be between -2 to =2=if not consider DCO
94
platelet level for DCO
should be 70,000 or greater, if not consider DCO
95
myxoid liposarcoma translocation
t(12;16)
96
synovial sarcoma translocation
t(X;18)
97
alveolar rhabdomyosarcoma translocation
t(2;13)
98
ewing sarcoma translocation
t(11;22)
99
clear cell sarcoma translocation
t(12;22)
100
innervation of teres minor
axillary nerve
101
innervation of supraspinatus
suprscapular nerve
102
innervation of infraspinatus
suprascapular nerve
103
innervation of teres major
lower subscapular nerve and thoracodorsal
104
innervation of suscapularis
upper and lower subscapular nerve
105
mutation in FGFR-3
Achondroplasia
106
mutation in glucoceribrosidase
Gaucher's dz
107
GNAS mutation
Fibrous displasia (shepherds crook proximal femur)
108
SLC26A2 gene which affects a sulfate transporter.
Diastrophic Displasia
109
mucopolysaccharidosis
due to accumulation of keratan sulfate and presents around 2 years of age with waddling gait, genu valgum, thoracic kyphosis, cloudy corneas, and normal intelligence. C1–C2 instability (due to odontoid hypoplasia) can be seen
Morquio’s syndrome
110
slowly adapting skin receptors that detect pressure, texture, and low frequency vibration and can be appropriately evaluated by static two-point discrimination.
Merkel's
111
rapidly adapting sensory receptor, is very sensitive to touch
meissner's corpuscle
112
ovoid in shape, measuring approximately 1 mm in length. They respond to high-frequency vibration and rapid indentations of the skin
pascinian corpuscle
113
slowly adapting receptors that detect stretching of the skin.
ruffinian
114
This method is used to compare the difference between two observed means.
Student's T test
115
Spinal muscular atrophy (SMA) is caused by a deficiency in
survival motor neuron protein
116
synovial sarcoma translocation
x,18
117
myxoid liposarcoma translocation
12,16
118
ewings translocation
11,22
119
clear cell sarcoma translocation
12,22
120
myxoid chondrosarcoma
9,22- BCR/ABL?
121
antibiotic that can precipitate serotonin syndrome
Linezolid, and benzo's reverse it
122
CA- MRSA with and w/o + D test what do you prescribe
IF D test is += this implies inducible resistance to clinda-and you must give oral doxy
if d test is negative- it is susceptible to clinda and you give clinda
If systemic signs of illness-give IV vanc
If superficial and mild infection-give Orals
123
level of study
"include randomized controlled studies with follow-up>80% and systematic review of Level-I RTC studies (homogenous studies)
Level I
124
this study level includes
evidence include case control studies, retrospective cohort studies and systematic review
level III
125
vidence include case control studies, retrospective cohort studies and systematic review
level II
126
evidence include case series with no control group (or compare to a historical control group)
level IV
127
level of evidence including expert opinion
level V
128
Rett Syndrome gene and ionhertience pattern
| Affects Grey matter of brain
X linked Dominant
C shaped Curve
Seizures
MECP2 gene mutation
129
type of collagen increased in OA
Type X collagen is seen in articular cartilage in the region of the interface with subchondral bone in most OA patients.
130
What is the role of the homeobox gene in the axial skeleton
regulate somitogenesis
131
Low serum phosphate and normal calcium levels are found in
X linked hypophosphatemic rickets
linked to the PHEX gene
ow serum phosphate, normal serum calcium and 25 hydroxycholecalciferol levels, and inappropriately low 1,25-dihydroxyvitamin D3.
*cannot activate the inactive form or Vit D
132
defect in mineralization of osteoid matrix caused by inadequate calcium and phosphate that occurs prior to closure of the physes
Rickets
| *osteomalacia after physis closes
133
deficient bone Quantity and Not quality of bone mineralizetion in adults
Osteoporosis
* disruption in mirco-arcitecture
* they have less total amount of normal appearing bone
134
NON nitrogen containing bisphosphonates
etidronate
clodronate
tiludronate
*mechanism of action
produce toxic atp analog
135
```
NITROGEN CONTAINING bisphosphonates
pamidronate
alendronate- fosomax
risderonate actonel
zoledronate reclast
ibandronate boniva
```
inhibit farnesyl pyrophosphate synthase
136
xray findings in peds rickets
increased physeal width and cortical thinning/bowing
rachitic rosary on ribs
137
Vitamin D resistant (familial hyphophosphatemic rickets)
| 3 types?
X linked- most common
Autosomal Dominant-
Autosomal recessive
138
Cause of X linked vitamin D resistant Familial Hypho-phosphatemic rickets
PHEX gen
leads to increased levels of FGF23, which decreases renal phosphate absorption and suppresses renal 25-(OH)-1α-hydroxylase activity
139
Characteristic of Familial Hypophosphatemic rickets
caused by inability of renal tubules to absorb phosphate
GFR is normal
vitamin D3 response is impaired
140
AD familial hyphophosphatemic rickets
results from mutation in FGF23
| leads to decreased FGF23 degradation
141
AR familial hypophosphatemic rickets
results from mutation in dentin matrix protein 1 (DMP1) gene
| leads to impaired osteocyte maturation and bone mineralization, and increased levels of FGF23
142
VIT D deficient (nutritional rickets) pathophysiology
low Vitamin D levels form diet lead to decreased intestinal absorption of calcium
low calcium levels leads to a compensatory increase in PTH and bone resorption
bone resorption leads to increased alkaline phosphatase levels
143
Only rickets with normal calcium
X linked hypophosphatemic rickets
144
renal osteodystrophy lab findings
Low calcium
High PTH
HIGH PHOSPHATE!! kidney suck and cant get rid of it
145
Hyperparathyroidism lab findingds
90% due to adenoma
| very low phosphate
146
Hypophosphatasia inheritance
auto recessive
147
Hypophosphatasia labs
high calcium
hi phosphate
very low Alk phosphate
148
caused by a mutation in the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP)
hypophosphatasia
149
phosphoethanolamine in the urine diagnostic for
hypophosphatasia
150
COMP is associated with
Multiple Epiphyseal Displasia type I
| Double patella
151
fibrillin is associated with
Marfan's syndrome
152
COL2A1 is associated with
SED tarda and SED congenita
153
RUNX2/CBFA is associated with
cleidocranial displasia
