general

Question 1

orientation of collagen fibers in superficial zone of cartilage

Answer 1

parallel to articular surface

Question 2

which zone has highest and lowest amounts of proteoglycans?

Answer 2

superficial zone has lowest, deep zone has highest

Question 3

orientation of collagen fibers in deep zone of cartilage

Answer 3

perpendicular to articular surface

Question 4

what type of collagen is seen in the physis?

Answer 4

type X

Question 5

what is decorin’s role in collagen?

Answer 5

important in controlling fibrillar collagen fiber diameter

Question 6

which cytokines are important in cartilage degradation?

Answer 6

IL-1, IL-6, TNF-alpha

Question 7

what is creep?

Answer 7

gradual deformation with constant loading

Question 8

what is the slope of a load-deformation curve?

Answer 8

stiffness

Question 9

what determines stiffness?

Answer 9

structural property based on material and shape of structure

Question 10

how do you calculate the strength of a cylinder?

Answer 10

third power of the radius

Question 11

what is the main stem cell driver in osteoblast formation?

Answer 11

RUNX2, aka CBF-alpha-1

Question 12

what mutation causes cleidocranial dysplasia?

Answer 12

heterozygous loss-of-function mutation in Cbfa-1 (RUNX2) gene

Question 13

what is denosumab?

Answer 13

RANK ligand inhibitor, dosed every 6 months

Question 14

what zone of the growth plate is affected by physeal fractures?

Answer 14

hypertrophic zone

Question 15

what zone of the growth plate does rickets affect?

Answer 15

hypertrophic zone

Question 16

what is vitamin D’s role in the RANK cascade?

Answer 16

vitamin D (cholecalciferol) is converted to 1-25 dihydroxycholecalciferol by the kidney –> upregulates RANKL produced by osteoblasts –> stimulates preosteoclasts

Question 17

nuclear factor for stem cell differentiation into adipose

Answer 17

PPARy2

Question 18

nuclear factor for stem cell differentiation into myoblast

Answer 18

MyoD

Question 19

how does PTH affect bone formation?

Answer 19

intermittent PTH –> increases bone formation. continuous PTH –> osteoclastogenesis –> bone resorption

Question 20

how are vitamin D levels best measured?

Answer 20

25 hydroxycholecalciferol (post hepatic metabolite)

Question 21

what is osteoconductive?

Answer 21

allows for bone ingrowth (provides the scaffolding)

Question 22

what is osteoinductive?

Answer 22

stimulates cells to become osteoblasts and make bone

Question 23

mechanism of non-nitrogen containing bisphosphonates

Answer 23

metabolized intracellularly to analog of ATP that is cytotoxic to macrophages

Question 24

cause of type 1 vitamin D-dependent rickets

Answer 24

defect in renal enzyme that activates Vitamin D in the kidney, autosomal recessive

Question 25

cause of type 2 vitamin D-dependent rickets

Answer 25

deficiency of vitamin D receptor, autosomal recessive

Question 26

what is sensitivity?

Answer 26

percentage of times that a positive test detects the diease

Question 27

what is specificity?

Answer 27

percentage of negative results seen in the absence of disease

Question 28

what does rifampin work on?

Answer 28

DNA-dependent RNA polymerase F

Question 29

which bacteria can become resistant to which antibiotics through active efflux pumps?

Answer 29

erythromycin, tetracycline

Question 30

which bacteria can become resistant to which antibiotics through alterations in the outer membrane porins?

Answer 30

B-lactams, tetracylcine, quinolones, trimethoprim

Question 31

what structure is predominant in crimp?

Answer 31

elastin

Question 32

which sensory nerve ending in tendon detects changes in muscle tension and pressure?

Answer 32

golgi tendon organs

Question 33

which sensory nerve ending in tendon detects change in pressure and movement?

Answer 33

pacini and ruffini corpuscles

Question 34

which sensory nerve ending in tendon are slowly adapting stretch receptors?

Answer 34

ruffini corpuscles

Question 35

which sensory nerve ending in tendon are rapidly adapting pressure receptors?

Answer 35

lamellated corpuscles

Question 36

which sensory nerve ending in tendons function as thermoreceptors and polymodal nociceptors?

Answer 36

free nerve endings

Question 37

what are the components of virchow's triad?

Answer 37

venous stasis, endothelial damage, hypercoagulability

Question 38

what activates protein C?

Answer 38

thrombin

Question 39

mechanism of heparin

Answer 39

activates antithrombin III

Question 40

mechanism of LDMWH

Answer 40

inhibition of factor Xa through antithrombin binding

Question 41

mechanism of warfarin

Answer 41

inhibition of vitamin K dependent carboxylation

Question 42

mechanism of argatraban

Answer 42

direct thrombin inhibitor

Question 43

mechanism of rivaroxaban

Answer 43

direct Xa inhibitor

Question 44

mechanism of aspirin

Answer 44

blocks thrombane 2

Question 45

mechanism of plavix

Answer 45

binds to platelets and blocks ADP mediated IIaIIIb receptor, platelet aggregation

Question 46

mechanism of TXA

Answer 46

competitively inhibits activation of plasminogen to plasmin (plasmin degrades fibrin)

Question 47

mechanism of nitrogen-containing bisphophonates

Answer 47

inhibit farnesyl pyrophosphate synthase (mevalonate pathway)

Question 48

mechanism of raloxifene

Answer 48

selective estrogen receptor modulator, acts on bone estrogen receptors to reduce osteoclast resorption

Question 49

mechanism of teriparatide

Answer 49

PTH derivative, receptors on osteoblasts activate, daily builds bone, continuous causes resorption

Question 50

mechanism of romosozumab

Answer 50

monoclonal Ig2 that activates Wnt pathway by binding sclerostin (which normally inhibits Wnt)

Question 51

methotrexate mechanism

Answer 51

folate analogue

Question 52

leflunomide mechanism

Answer 52

inhibits pyrimidine synthesis

Question 53

hydroxychloroquine mechanism

Answer 53

blocks activation of toll-like receptors (TLRs) which decreases activity of dendritic cells

Question 54

etanercept mechanism

Answer 54

binds to TNF-alpha

Question 55

infliximab mechanism

Answer 55

human mouse chimeric anti-TNF alpha monoclonal antibody

Question 56

anakinra mechanism

Answer 56

recombinant IL-1 receptor antagonist

Question 57

rituximab mechanism

Answer 57

monoclonal antibody to CD 20 antigen

Question 58

abatacept mechanism

Answer 58

inhibits T cells by binding to CD 80 and CD 86

Question 59

tocilizumab mechanism

Answer 59

IL6 receptor inhibitor

Question 60

stress equation

Answer 60

force/area

Question 61

strain equation

Answer 61

change in length/original lengthwh

Question 62

what property is represented by the area under the stress/strain curve

Answer 62

toughness

Question 63

what is young's modulus?

Answer 63

measure of stiffness (ability to resist deformation) of a material in the elastic zone. slope of stress/strain curve in elastic zone

Question 64

what is a brittle material

Answer 64

linear stress/strain relationship until point of failure, elastic deformation only, little to no plastic deformation

Question 65

what is a ductile material

Answer 65

large amount of plastic deformation before failure

Question 66

what is an isotropic material

Answer 66

same mechanical properties in all directions (like a golf ball)

Question 67

what is an anisotropic material?

Answer 67

different mechanical properties depending on the direction of the applied load (like bone)

Question 68

resorption rates of bone graft substitutes (fastest to slowest)

Answer 68

calcium sulfate -> tricalcium phosphate -> hydroxyapatite

Question 69

what bone graft has the highest compressive strength?

Answer 69

calcium phosphate

Question 70

what are the properties of DBM?

Answer 70

osteoinductive and osteoconductive

Question 71

what are the properties of allograft?

Answer 71

osteoconductive only

Question 72

what are the properties of BMPs?

Answer 72

osteoinductive only

Question 73

what cell type expresses RANKL?

Answer 73

osteoblasts

Question 74

what cell type has RANK receptors?

Answer 74

osteoclasts

Question 75

what cells secrete osteoprotegrin?

Answer 75

osteoblasts

Question 76

osteoblast origin

Answer 76

undifferentiated mesenchymal stem cells

Question 77

osteoclast origin

Answer 77

monocyte/macrophage cell lineage

Question 78

do TGFb and IL10 stimulate or inhibit osteoclasts?

Answer 78

inhibit