Joint Tissues Flashcards

1
Q

What does tissue function depend on?

A

cell structure and function - determined by extracellular components

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2
Q

What is the study of how different materials and structures are able to provide support in response to changing forces?

A

mechanical behavior of tissue (deals with relationship between stress and strain)

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3
Q

What is the resistance of a material to deformation?

A

stress

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4
Q

What is stress “formula”?

A

force/unit area

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5
Q

What is the deformation that occurs in a material in response to the application of an external load quantified as a percentage of change?

A

strain

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6
Q

What are isotropic materials?

A

homogenous, exhibit uniform properties when loaded in different directions

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7
Q

What are anisotropic materials?

A

heterogenous, exhibit non-uniform properties when loaded in different directions

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8
Q

What is the application of a force, moment, or combination of them to a material?

A

load

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9
Q

What force is equal and opposite loads applied away from the surface of a structure?

A

tension

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10
Q

What does tension result in?

A

lengthening and narrowing of structure and causes tensile stresses to occur

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11
Q

What force is equal and opposite loads applied toward the surface of a structure?

A

compression

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12
Q

What does compression result in?

A

shortening and widening and causes compression stress

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13
Q

What force is opposing loads applied parallel to the surface of a structure?

A

shear

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14
Q

What does shear result in?

A

internal angular deformation and leads to shear stress

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15
Q

What force is opposing loads are applied to the surface of a structure resulting in twisting about an internal axis?

A

torsion

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16
Q

What does torsion result in?

A

compression and tension and shear stresses

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17
Q

What is bending?

A

three or more loads applied to a structure causing it to bend about an axis external to itself

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18
Q

What is combined stress?

A

combination or two or more loading modes applied to a structure at the same time

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19
Q

What is deformation?

A

change occurring in some dimension of the material in response to an applied load

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20
Q

What region of the load-deformation curve signifies the removal of slack within a structure as tensile load is applied?

A

toe region

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21
Q

What region of the load-deformation curve signifies the range in which stress is directly proportional to strain but all the deformation will return to normal after load removal?

A

elastic range

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22
Q

What part of the load-deformation curve signifies the end of the elastic region when load goes to permanent deformation?

A

elastic limit/yield point

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23
Q

What region of the load-deformation curve is the range in which deformation occurs at a rate disproportional to stress and permanent structure remains intact?

A

plastic region

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24
Q

What is the point of the load-deformation curve in which continued load and max load is reached and deformation continues until failure?

A

ultimate failure point

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25
Q

What region of the load-deformation curve does the removal of crimp occur?

A

toe region

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26
Q

What effect does increasing fiber quantity have on response to load?

A

increases strength, stiffness, and elongation to failure is the same - can resist more load

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27
Q

What effect does increasing fiber length have on response to load?

A

increases elongation to failure, strength remains, stiffness decreases

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28
Q

What is Young’s modulus?

A

linear portion of the curve in the elastic region measuring the stiffness/resistance to the external loads (inverse = compliance)

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29
Q

If the slope is steep and modulus is high, material exhibits _ stiffness and _ compliance.

A

high, low

30
Q

Name an example of high stiffness, low compliance in the body.

A

cortical bone

31
Q

If the slope is gradudal and modulus is low, material exhibits _ stiffness, _ compliance.

A

low, high

32
Q

Name an example of low stiffness, high compliance in the body.

A

adipose tissue

33
Q

What is the stress-strain curve?

A

load-deformation curve in which load is expressed as load per unit area and strain is expressed as deformation per unit of length or percentage of deformation

34
Q

The following characteristics explains what region of the stress-strain curve for collagenous materials?

very little force to deform tissue in straightening crimp,
tests for ligament integrity when performed on non-injured ligaments, slack taken up in tendon by its attached muscle before force is transmitted to bone

A

toe region

35
Q

The following characteristics explains what region of the stress-strain curve for collagenous materials?

Collagen fibrils are being stretched and are resisting applied force
reflects the type of collagen, fibril size, and cross-linking among collagen molecules
when the load is removed, structure will return to its pre-stressed dimensions (will take time)
includes stress and strains that occur within normal activities
typically extends to about 4% strain

A

elastic region

36
Q

The following characteristics explains what region of the stress-strain curve for collagenous materials?

failure of collagen fibers begins,
structure no longer capable of returning to OG length after force is removed
recovery requires considerable time - healing

A

plastic region

37
Q

What are clinical examples of plastic region injuries?

A

Grade I and II ligament sprains/tendon strains

38
Q

The following characteristics explains what region of the stress-strain curve for collagenous materials?

remaining collagen fibrils experience increased stress and rapidly rupture sequentially
creates overt failure of the tissue

A

beyond ultimate failure point

39
Q

Failure through the middle of a ligament or tendon is called what?

A

rupture

40
Q

Failure at bony attachment of a ligament or tendon is called what?

A

avulsion

41
Q

Failure within bony tissue is called what?

A

fracture

42
Q

Deformation prior to failure depends on what things?

A

tissue type and size

43
Q

What is the ability of a material to resist flow and dampen shear forces?

A

viscosity

44
Q

What is the ability of a material to return to its OG shape following deformation?

A

elasticity

45
Q

What are the time-dependent properties?

A

creep, hysteresis, stress-relaxation

46
Q

What is creep?

A

progressive strain or deformation of a structure under the influence of a constant stress/load

47
Q

True/False: For creep, Force remains constant while length changes.

A

true

48
Q

What might creep be applied to in the clinical setting?

A

stretching a shortened tissue - constant force applies and tissue gradually elongates

49
Q

What is stress-relaxation?

A

decrease in stress within a structure in the presence of a constant strain

50
Q

What does stress-relaxation look like in clinical setting?

A

therapist may perceived this as a reduced resistance to stretch ex: prolonged static splinting

51
Q

What is hysteresis?

A

lag of an effect when forces acting upon a material are changes (energy lost as heaT)

52
Q

What are the determinant properties of fibrous connective tissue?

A

size and density of the structure, mechanical properties and proportion of collagen and elastin, orientation of fibers in the tissue

53
Q

Which of the following is not a mechanical property of fibrous connective tissue?

a. high tensile strength
b. anisotropic
c. stiffness changes with changes in speed of loading
d. have significant viscoelastic characteristics

A

c - stiffness does not change

54
Q

Fails at strains occurs as low as 9% for stuctures with _ elastin fiber content.

A

little/no

55
Q

Fails at strains occur up to 70% for structures with _ elastin content.

A

high

56
Q

True/False: Ultimate load and strain increase with increasing speed of loading.

A

true

57
Q

True/False: Aging results in general loss of collagen content, but increase in collagen cross-linking.

A

true

58
Q

True/False: The use of NSAIDs can cause a decrease in the tensile strength of CTs due to a decrease in collagen content and in the proportion of non-soluble collagen.

A

false - increase

59
Q

What are the mechanical determinant properties of cartilage?

A
type (e.g. hyaline),
structural composition (i.e. Type I vs II),
proportions of structural components (i.e. eater, collagen, elastin, proteoglycans)
60
Q

Which of the following is not true for cartilage?

a. anisotropic
b. biphasic
c. capable of large visoelastic deformation
d. injury/pain is felt immediately

A

d - injury can often occur without initial awareness and can progress until tissue destruction is quite advanced before pain is experienced

61
Q

What are the mechanical determinant properties of bone?

A

size, density, and geometry;
mode of loading applied;
rate and frequency of loading

62
Q

What are the mechanical properties of cortical bone?

A

very high ultimate strength in compression and tension,
very high stiffness,
Fx’s @ ~2% strain,
stiffness and ultimate load increase with increased speed of loading

63
Q

What are the mechanical properties of cancellous bone?

A

mod to low ultimate strength depending on porosity,
moderate to low stiffness,
anisotropic,
Fx’s @ ~ 7% strain but can sustain as high as 75% before failure in some instances,
stiffness and ultimate load tolerance increase with increased speed of loading

64
Q

True/False: Changes in the mech. properties of bone generally parallel changes in bone mass.

A

true

65
Q

Where are the stresses on bone from?

A

WBing and muscle loading

66
Q

What type of tension does a dynamic splint provide?

A

spring-loaded = aids in restoration of knee ext

67
Q

What occurs during static progressive splinting?

A

apply torque as close to EoR as possible, stress-relaxation, force required to maintain decreases over tine and then adjust to new setting to progress

68
Q

What are some clinical scenarios to utilize open chain exercise?

A

OA, NWBing, ligament tear, cartilage

69
Q

What are some clinical scenarios to utilize closed chain exercise?

A

strength, function, bone remodeling (compression), motor unit activity (= increased muscle effort around a joint)

70
Q

Delayed onset muscle soreness is due to what phase of contraction?

A

eccentric