MRC Basic Science Flashcards
Hooke’s law.
Stress directly proportional to strain.
Point at which permanent deformation occurs.
Yield point.
If stress is removed then strain decreases to zero.
Elastic deformation.
Stress-strain curve zone to the right of the elastic region.
Plastic region.
If stress is removed then strain is not recovered.
Plastic deformation.
Origin to yield point in stress-strain curve.
Elastic region.
Yield point to ultimate strength point in stress-strain curve.
Plastic region.
Sress-strain curve zone to the right of the plastic region.
Necking region.
Stress-strain curve region from ultimate strength point to failure point of stress-strain curve.
Necking region.
Stiffness of a material is a measure of ____ deformation
elastic
Toughness of material.
Area under stress-strain curve.
Difference between yield point and fracture point characterizes this.
Ductility of material.
Strength of material characterized by this.
Maximum stress before failure.
Constant stress but change in strain over time.
Creep.
Constant strain but change in stress over time.
Stress relaxation.
Loading and unloading of material causes dissipation of energy.
Hysteresis.
Metal is an isotropic or anisotropic material.
Isotropic.
Titanium alloy used.
Titanium, aluminum, vanadium
Ceramic on ceramic hip material.
Alumina.
Ceramic material with poly bearing.
Zirconia.
PMMA stiffness falls here.
Between cortical and cancellous bone.
Dextro (D) lactide monomor with bioabsorbable screws assoicated with this.
Rapid bone resorption and inflammatory response.
Viscoelastic behavior with nonlinear elasticity is evidenced by this.
Toe region.
Responsible for toe region of ligament.
Elastin.
Stiffness of plate construct proportional to this.
Plate thickness to third power.
IMN stiffness proportional to this.
Radius to fourth power.
Most important factors of ex-fix stiffness (2).
- Fracture reduction
2. Large pin diameter
Primary mechanism of lubrication for cartilage.
Elastohydrodynamic.
Runx2
Osteoblast
Sox9
Chondrocyte
PPAR-gamma
Adipocytes
PTH uses ____ ____ as mediator for cell signaling.
adenylyl cyclase
Osteocytes are these former cells.
Former osteoblasts trapped in matrix they produced.
Osteocytes inhibit osteoblasts via this molecule.
Sclerostin.
PTH increase/decrease sclerostin?
Increase
Calcitonin increase/decrease sclerostin?
Decrease
Osteoclasts absorb this.
Mineralized matrix.
How do osteoclasts bind to the bone?
Vibronectin (integrin).
Major protelytic enzyme for bone digestion.
Cathepsin K.
Osteoprotegrin does this.
Inhibits RANKL.
Osteoblast differentiation pathway.
Wnt -> beta-catenin -> Runx2
RANKL decoy receptor.
OPG (osteoprotegrin)
Enzyme that breaks down cartilage matrix.
MMP13
Peak bone mass is in this decade.
Third decade.
Clonazepam increases/decreases sclerostin.
Increases.
Besides T-score, what other score guides treatment of osteoporosis.
FRAX score.
Duration of bisphosphonate treatment prior to atypical subtroch fracture.
4 years.
Teriparatide (forteo) has the theoretical risk of this.
Secondary chondrosarcoma.
IgG2 antibody to RANKL.
Denosumab.
Sclerostin antibody.
Romosozumab.
Most prominent tendon proteoglycan.
Decorin.
