Exam 1 Part 3

Question 1

What are the 4 components of soft tissue?

Answer 1

collagen, elastin, ground substance, and water

Question 2

T/F: Collagen has continuous metabolic turnover through growth to maturity and becomes more stable at maturity.

Answer 2

True

Question 3

What soft tissue component is synthesized and secreted by the fibroblasts?

Answer 3

collagen (molecules)

Question 4

T/F: Once secreted by fibroblasts, collagen molecules align in extracellular matrix in a crossing arrangement.

Answer 4

False; parallel arrangement

Question 5

T/F: Collagen can stretch to 150% of original length without breaking.

Answer 5

False; 110%

Question 6

T/F: Immobilization can lead to decreased diameter, density, number, mass, and metabolism of collagen fibers and fibrils.

Answer 6

True

Question 7

T/F: Elastin can stretch to 150% of original length without breaking.

Answer 7

True

Question 8

What amorphous gel-like substance surrounding the cells is aka “Cement Substances?”

Answer 8

Ground Substance

Question 9

What are the 4 major GAGs?

Answer 9

Hyaluronic acid, Chondroitin-4-sulfate, Chondroitin-6-sulfate, and Dermatan sulfate

Question 10

T/F: Hyaluronic acid and water is a powerful lubricant which maintains a critical distance between collagen fibers.

Answer 10

True

Question 11

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?

Answer 11

Deformation

Question 12

T/F: Shear forces are a combination of tensile and compressive loads.

Answer 12

False; this is true of bending forces, shear forces occur when a load is applied parallel to the surface of the structure.

Question 13

What kind of force is stretching or pulling? twisting?

Answer 13

tension;

torque

Question 14

T/F: tensile forces occur in the IVD during rotational movements and the annular fibers tend to bear the tensile load.

Answer 14

True

Question 15

What are the triceps surae muscles?

Answer 15

soleus and two heads of the gastrocnemius

Question 16

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?

Answer 16

cartilaginous endplate=nuclear herniation;
Schmorl’s node;
Compression fractures

Question 17

T/F: compressive loads applied with torque are transmitted through the facets, leading to capsular injuries.

Answer 17

False; this is true of compressive loads in extension

Question 18

What can result from compressive loads applied with torque?

Answer 18

circumferential tears in the annular fibers of the IVD

Question 19

Bending is a combination of compression and tension forces. What type of bones are frequently fractured from bending?

Answer 19

long bones

Question 20

What bones are most at risk for fracture from shear forces? What specific parts of the spine resist shear forces?

Answer 20

cancellous bones;

facet joints and the fibers of the annulus fibrosus

Question 21

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?

Answer 21

90%;

the annulus

Question 22

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.

Answer 22

torque

Question 23

T/F: Strain measure the intensity of the force, and stress measures the degree of deformation.

Answer 23

False; vice-versa

How stressful is Palmer? It’s intense.
How bad was the muscle strain? It’s deformed.

Question 24

In addition to stress and strain, what other qualities are represented by the Stress/Strain Graph?

Answer 24

Strength, Ductility, Toughness

Question 25

What is the maximum stress a tissue can withstand without permanent deformation?

Answer 25

strength

Question 26

What is the stress at the yield point of a material beyond which permanent deformation will occur?

Answer 26

yield stress

Question 27

What is the maximal stress that a material can withstand prior to the initiation of failure?

Answer 27

Ultimate strength

Question 28

What is the stress at which the material actually breaks or ruptures?

Answer 28

failure strength

Question 29

What is represented by the steepness (slope) of the stress/strain curve?

Answer 29

ductility

Question 30

What does it mean if tissues are ductile?

Answer 30

It means they are pliant; tissues fail at low stress but can withstand a large strain

Question 31

If tissues can withstand high stress but fail with relatively low strain, how are these tissues described?

Answer 31

brittle (stiff)

think bones