Exam 1 Part 3 Flashcards
What are the 4 components of soft tissue?
collagen, elastin, ground substance, and water
T/F: Collagen has continuous metabolic turnover through growth to maturity and becomes more stable at maturity.
True
What soft tissue component is synthesized and secreted by the fibroblasts?
collagen (molecules)
T/F: Once secreted by fibroblasts, collagen molecules align in extracellular matrix in a crossing arrangement.
False; parallel arrangement
T/F: Collagen can stretch to 150% of original length without breaking.
False; 110%
T/F: Immobilization can lead to decreased diameter, density, number, mass, and metabolism of collagen fibers and fibrils.
True
T/F: Elastin can stretch to 150% of original length without breaking.
True
What amorphous gel-like substance surrounding the cells is aka “Cement Substances?”
Ground Substance
What are the 4 major GAGs?
Hyaluronic acid, Chondroitin-4-sulfate, Chondroitin-6-sulfate, and Dermatan sulfate
T/F: Hyaluronic acid and water is a powerful lubricant which maintains a critical distance between collagen fibers.
True
When in static equilibrium, if an object is subjected to external forces, some local shape change will occur within the object. What is this local shape change known as?
Deformation
T/F: Shear forces are a combination of tensile and compressive loads.
False; this is true of bending forces, shear forces occur when a load is applied parallel to the surface of the structure.
What kind of force is stretching or pulling? twisting?
tension;
torque
T/F: tensile forces occur in the IVD during rotational movements and the annular fibers tend to bear the tensile load.
True
What are the triceps surae muscles?
soleus and two heads of the gastrocnemius
Where does mechanical failure occur first in the spine as a result of compressive forces? What is the result of this? What would additional failure to withstand compressive forces result in?
cartilaginous endplate=nuclear herniation;
Schmorl’s node;
Compression fractures
T/F: compressive loads applied with torque are transmitted through the facets, leading to capsular injuries.
False; this is true of compressive loads in extension
What can result from compressive loads applied with torque?
circumferential tears in the annular fibers of the IVD
Bending is a combination of compression and tension forces. What type of bones are frequently fractured from bending?
long bones
What bones are most at risk for fracture from shear forces? What specific parts of the spine resist shear forces?
cancellous bones;
facet joints and the fibers of the annulus fibrosus
What percent of the resistance to torque of a motion segment is provided by the IVDs? what part provides the majority of the torsional resistance?
90%;
the annulus
Fx of impacted facet joint, fx or pars interarticularis, capsular tears, circumferential tears of the annulus, and spiral fx are all example of failure that result from excessive _____ force.
torque
T/F: Strain measure the intensity of the force, and stress measures the degree of deformation.
False; vice-versa
How stressful is Palmer? It’s intense.
How bad was the muscle strain? It’s deformed.
In addition to stress and strain, what other qualities are represented by the Stress/Strain Graph?
Strength, Ductility, Toughness
What is the maximum stress a tissue can withstand without permanent deformation?
strength
What is the stress at the yield point of a material beyond which permanent deformation will occur?
yield stress
What is the maximal stress that a material can withstand prior to the initiation of failure?
Ultimate strength
What is the stress at which the material actually breaks or ruptures?
failure strength
What is represented by the steepness (slope) of the stress/strain curve?
ductility
What does it mean if tissues are ductile?
It means they are pliant; tissues fail at low stress but can withstand a large strain
If tissues can withstand high stress but fail with relatively low strain, how are these tissues described?
brittle (stiff)
think bones
