Exam 1 Prep Flashcards by Julia Mooney

Biomechanics

The use of the laws of physics to describe motion of the body and its forces

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What makes up a synovial joint?

-Ends of bones
-Cartilage
-Menisci
-Ligaments
-Tendons
-Joint capsule
-Synovium
-Muscle & tendon

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What does synovial fluid do?

Lowers the coefficient of friction in the joint and prevents wear and tear

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What are the functions of muscles?

-Statically: to stabilize isometric contractions
-Dynamic: to move (concentric and eccentric contractions)

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What are the four basic types of body tissues?

-Thelial
-Nerve
-Muscle
-Connective

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What are the 5 basic types of connective tissue?

-Blood
-Fat
-Bone
-Cartilage
-Ordinary (ligaments, tendons, fascia, neural coverings)

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What are the 3 components of all connective tissues?

-Cells (blasts, cytes)
-Extracellular matrix (proteoglycans)
-Fibers (collagen, elastin)

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What is the role of proteoglycans in connective tissue?

They imbibe water and resist compression

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What are the properties of collagen?

Collagen is more stiff and resists tension

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What are the properties of elastin?

Elastin has more give than collagen, but it still resists tension

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What connective tissues have the best order with individual fibers?

Tendons & ligaments

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What is the most abundant protein in the body?

Collagen

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In what specific joint in the body are there a lot of proteoglycans found?

There are a lot of proteoglycans found in intervertebral discs because they need to resist compression to protect the spine. There are also high concentrations in synovial fluid.

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What are the properties of bone?

-Bone needs to resist stress in all directions
-It contains collagen fibers and inorganic salts

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Cartilage

Needs to resist compression

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What is the connective tissues response to lack of stress?

-Leads to loss of strength in the connective tissue
-Loss of proteoglycans
-Irregular pattern of collagen cross linking

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What is the weakest type of tissue in the body?

Connective tissue is the weakest link

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What are the 3 different body planes?

-Frontal
-Sagittal
-Transverse

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What movements occur in the frontal plane?

Abduction and adduction

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What movements occur in the sagittal plane?

Flexion and extension

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What movements occur in the transverse plane?

Rotation

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Kinematics

the set of concepts that allows us to describe displacement or motion without thinking about the forces that cause the movement

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Kinetics

The study of the forces that are causing the movement

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One degree of freedom

The freedom to move through one plane

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What are the two types of motion?

-Linear -Angular (rotatory)

Osteokinematics

physiologic motions (i.e. flexion/extension)

Arthrokinematics

understanding the movement occurring at the joint surfaces

Loose pack position

-Structures are most lax -Greatest amount of joint play -Usually at midranges

Close pack position

-Usually at end ranges -Structures surrounding the joint are taught -Most stable position

Describe the arthrokinematics of a concave bone surface rotating on a convex bone surface

The concave surface is rotating upwards and gliding upwards in the same direction

Closed kinematic chain

When two ends are fixed

Open kinematic chain

One end of the chain is moving, and the other is fixed

Stress

Amount of force on a tissue

Strain

amount of give that occurs in a material in response to stress

Explain stress-strain to failure

A tissue has a certain amount of strain that it can take, at high stress there is a lot of strain on the tissue and at some point, it will reach its fracture or breaking point. Example: you can stretch a rubber band pretty far and it gets easier and easier to stretch it the more you go, and at some point the rubber band reaches its failure point and breaks

What are the different regions in the stress-strain curve?

-Toe region (not much stress) -Elastic region (tissue is starting to stretch and have more stress-strain) -Plastic region (tissue is in a lot of stress but not quite at failure, tissue starts to get microtears) -Failure point (tissue reaches its failure point and breaks)

When do tendon ruptures commonly occur?

Tendon ruptures usually occur during eccentric loading

What percentage of strength is lost in ligaments at 6-9 weeks of immobilization?

up to 50%

What two types of tissues are capable of excitation?

Muscle and nerve tissue

What is the definition of torque?

The perpendicular force X the length of the lever arm

What are the three different lever systems?

-First class (teeter totter, fulcrum in middle) -Second class (wheelbarrow, fulcrum is on opposite site of force) -Third class (hammer, fulcrum is on the side the force is produced)

What are the two types of muscle fibers?

-Type 1: Slow twitch -Type 2: Fast twitch

What type of muscle architecture can produce the most force?

Pennate muscles

What type of muscle architecture can move a bony lever the most?

strap

Length-tension relationship

Optimal force generation occurs when the muscle is slightly beyond its resting length and is slightly stretched

Active insufficiency

when the muscle becomes shortened to the point that it cannot generate much force/tension

Passive insufficiency

when the opposing muscle becomes stretched to the point where it can no longer lengthen

Concentric

A shortening contraction

Eccentric

A lengthening contraction

Isokinetic exercise

set speed but variable resistance

Force-velocity relationship

-An inverse relationship -As force increases, velocity decreases -As velocity increases, force decreases

Where is the center of mass in the body?

Just anterior to S2 at the top of the pelvis

Newton's 1st law

a body at rest will stay at rest, and a body in motion will stay in motion until an outside force acts on it

Newton's 2nd law

acceleration of a body is proportionate to the magnitude of the force acting on it and inversely proportional to the mass (F=ma)

Newton's 3rd law

For every action, there is an equal and opposite reaction

What is the definition of work?

force times the distance traveled

Power

ability to maintain work over time

Strength

relative ability to generate force

Endurance

Ability to continue muscular effort for a prolonged period of time

How can muscular performance be measured?

It can be measured using torque

Range of motion

angular displacement of the lever arm

Angular velocity

speed of the lever arm

Peak torque

the highest point on the moment-angular position curve

Work (isokinetic exercise)

area under the curve

Describe the arthrokinematics of a convex bone surface rotating on a concave bone surface

The convex surface is rotating in one direction and gliding on the concave surface in the opposite direction