bio 442 exam 1

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what can you apply to a lever to lift or work against a resistance

effort

class 3 lever

effort is between the fulcrum & load

what does creep contrast from

elastic material which doesn't exhibit an increase deformation no matter how long the load is applied

2 functions of having elastin in ligaments

elastic protein store & recovery energy

toe region of tendons

elongation accompanied by very low stress initial low stiffness

measurement of material properties in tendons

end effect, toe region problem, grip

when an interaction ceases, the 2 objects do what

no longer experience the force

orientation of collagen fibers of woven bone

random

work & power

rate at which energy is transferred is an important performance vector

steroids & exercise

rate of muscle growth doesn't allow tendons enough time to adapt

plastic region

region after the yield point, before failure

what does a non-linear s-s curve neglect that other graphs do not

viscoelastic behavior

what do proteoglycans influence in ligaments

viscoelastic properties

delta x =

vit + 1/2at^2

tangental velocity =

w (angular velocity) x r (position vector)

what type of axis does bending create

neutral

articular cartilage doesn't have what

blood, lymph nodes, & nerves

calcified zone transitions into what

bone

what has more proteoglycans

bone

what property is rarely seen with pure tension

bone

chondrocytes are responsible for what

cartilage formation

degree to radians

(given degree)(pi/180)

radians to degree

(radians)(180/pi)

Egi =

-mgh

at physiological stresses when can a rupture not occur after

15 days

what type of collagen is mostly in articular cartilage

2

how much water are in ligaments

2/3rds

by 90 years old, how much % of bone to women loose

20% cortical & 50% trabecular

how much to compressive properties of cartilage vary by depth

20x (due to proteoglycan content or collagen fiber arrangement)

what class of levers are most joints

3

peak bone mass is obtained before what age

30

failure % of stress at 40 weeks from ligament scar material

35

how much % of bone's dry weight is organic

35

ostotendinous junction components in cancellous bone

4 layers (normal tendon, fibrocartilage, calcified cartilage, bone)

how much % of people have osteoarthritis when over 60 years of age

50

how much of bone is evolutionary conserved across mammals

63-70%

failure % of force at 40 weeks from ligament scar material

65

how much % of bone's dry weight is mineral

65

how much % what is articular cartilage

65-80

what % of collagen contributes to the dry weight of ligaments

70-80

gravity on earth's body

9.81 m/s2

how much % of the organic matrix is collagen

95

stress =

F(internal force)/A(cross-sectional area)

work units

J

W is equivalent to what

J/s OR Nm/s

J is equivalent to what

Nm & kg m/s2

impulse units

Ns

what does a lever amplify

an input force to provide a greater output force

forces only exist as a result of what

an interaction

power units

W (watts)

an impulse represents what

a change in momentum

magnetic force

a consequence of the electromagnetic force

what is the transition from tendon to fibrocartilagneous tissue characterizes by

a dense proteoglycan sound substance

according to newton's 2nd law since there is an acceleration in centripetal force there must be what

a force inwards

whenever there is an interaction between 2 objects what is there

a force upon each of the objects

kinematic equations describe motion as what

a function of time

creep failure in tendons

a material fails under prolonged contact stress

what is a class 2 lever also called

a multiplier force

what are chondrocytes surrounded by to protect the cell

a perpendicular matrix

primary bone needs what

a pre-existing substrate

woven can be deposited fast without what

a pre-existing substrate

force

a push or pull upon an object resulting from the object's interaction with another object

during a collision, an object experiences a force for what

a specific amount of time

best control involves what

a stiff tendon

what does the connection between the golgi tendon organ & the tendinous fascicles send

a thick, myelinated afferent fibre to the spinal cord

example of motions in the frontal plane

abduction & adduction

when do fibroblast appear in ligament healing

about a week

example of anisotropy

absorbance

how does menopause affect bone loss

accelerates it

law of acceleration

acceleration is produced when a force acts an a mass (f=ma) the greater the mass, the greater the amount of force needed to accelerate it

risk factors for osteoarthritis

age, obesity, genetics, injury

volkmann's canal

all osteons & smaller & perpendicular to bone

why is injury a risk factor for osteoarthritis

altered loading (unloading & overloading of involved & uninvolved)

contact area in the joint increase when what occurs

an increase in force application

law of interim

an object @ rest will remain @ rest unless acted upon by an unbalanced force an object in motion continues in motion with the same speed & in the same direction unless action upon by an unbalanced force

rotation is what type of motion

angular

torque is required for what type of acceleration

angular

internal tendon

aponeurosis portion of tendon inside tendon looms like a sheet

types of contact forces

applied, normal, tension, air resistance, friction, spring forces

scaling

area increases as length2 mass increases as length3 mass increases etc

toughness

area under the s-s curve

flaws of scar morphology

areas will have holes which will increase stress concentration which is present at 14 weeks

when is the gap closed during ligament healing

around 3 days

fiber alignment is normalized when

at 14 weeks

objects included in mechanics

atomic particles in the universe

4 ligament functions

attached articulating bone across a joint, guide joint movement, maintain joint congruency, & proprioception

efferent

away from CNS

where is the toe region on a s-s curve

beginning

what 2 stresses are the most common combined loads in the skeletal system

bending & compression

haversian canal

bigger than vascular channel in primary osteon

is diffusion or blood a more efficient way to transfer nutrients

blood

blood cells with ligament healing

blood cells with clot initially

ligament structure order

bone --> calcified fibrocartilage --> fibrocartilage --> ligament

osteoblasts

bone producing cells/immature cells

if bone was just cortical what would happen

bone would be heavier

how are ligaments & tendon similar structurally

both have similar hierarchal structures with successive bundles

fast strains are more likely to what

break bone

osteoclasts

break down & absorbs

woven bone comes from what

broke bones

what type of bone is irregular/short bones composed of

cancellous

toe region problem in tendons

cannot find the zero point & can make definitions hard

torque

capability of a force

which has more proteoglycans - cartilage or ligaments

cartilage

muscle weakness could be related to what

cartilage degeneration

what is organic material of the bone

cells & water

velocity =

change in position/change in time

how to calculate movement

change in positon/change in time

acceleration =

change in velocity/change in time

2 ways to bring a lever to equilibrium

change mass & distance

tendons & disuse

changes are largest near the muscle muscle tendon junction is weaker decreased collagen production smaller collagen fibers

examples of potential energy

chemical, gravitational, elastic

cells on articular cartilage

chondrocytes

following an injury what do chondrocytes do

cluster & produce the matrix

friction =

coefficient of friction (u thing) x normal force (N)

scar biochemistry in ligaments

collagen cross linking stronger when more interconnection between ropes scar tissue cross linking dramatically reduced cross link density is 50% at 40 weeks

when the muscle contracts tension is transferred to the tendon causing what

collagen fibers to compress the nerve & initiate action potentials

linear region of the non-linear s-s curve

collagen fibril backbones becoming stretchy yielding a stiffer material

what 3 things make up the cartilage matrix

collagen, proteoglycans, & other proteins

examples of spring like material in the human body

collagen, tendons & ligaments, skin, & foot

mechanical properties of bone

combination of the structural & the material properties of bone

what type of material is bone

composite material

articular cartilage is loaded in what

compression

how do bones typically load

compression force

3 mechanical properties of cartilage

compressive, tensile, & shear

articular cartilage is a network of what

connective protein

synovial sheath

connective tunnel the tendon moves in holding tendon close to the joint structure

the multilayered fibre bundle organization of a tendon allows for the maintenance of high tensile strength with what

considerable flexibility in bending

3 types of forces

contact, non-contact, & centripetal forces

compliant tendons complicate what

control

2 types of bones

cortical & cancellous

3 types of viscoelastic elements

creep, stress relaxation, & rate dependency/hysteresis

what pattern do ligaments have

crimp

calcified zone function

decrease stress concentration

how does aging affect cellularity in ligaments

decreased

tendons & aging

decreased cross-sectional area increased cross-linking more small fibers no change in modulus more prone to fatigue failure

smaller collagen fibers -->

decreased material properties

articular cartilage helps with what

decreasing friction

which zone has the highest proteoglycan concentration & lowest water content & permeability

deep zone

which zone is best at resisting compressive loads with a poisson ration of 0.5

deep zone

creep increases what

deformation under a constant load

strain =

delta L/L(length)

kinematics

description of motion which includes the consideration of time, displacement, velocity, acceleration, & space

diaphysis

develops from primary ossification (shaft) the hollow shaft of a long bone, made up of cortical bone & usually contains bone marrow & adipose tissue surrounded by medullary cavity

highly organized structure each right with fibers aligned in what

different directions to force

vectors have what

direction & magnitude

example of vectors

displacement, velocity, weight, gravity, force, & acceleration

example of scalars

distance, mass, speed, density, time, length, area

moment of inertia

distribution of mass within an object tendency for a body to resist angular acceleration

levers apply what to a load

effort

3 ways to measure material properties in ligaments

end effects, ligament cross-sectional area, & zero strain. position

what are fascicles surrounded by

endotenon ( a ct sheathe with proteoglycans & elastin & contains blood, lymphatic vessels, & nerves)

1st law of thermodynamics

energy cannot be created or destroyed, only transformed from 1 from to another

work

energy transferred to or from an object by application of a force

what are fascicle bundles surrounded by

epitenon

who was the pioneer for biomechanics

etienne jules mary in 1880

what would happen if normal force did not exist

everything would collapse on itself

what is a consequence of the folded structure of the myotendinous junction

facilitate the transfer of land by shear rather than tension which creates an acute angle of contact between muscle & tendon tissues

fatigue failure in tendons

failure of material subjected prolonged cyclical loading

fascinates aggregate into what

fascicle bundles

fibre bundles are aggregated to form what

fascicles

medullary cavity

fat storage site lined by a thin, largely cellular ct membrane not in flat bones

what 4 aspects reduce after disuse in ligaments

fiber #, collagem content, cross linking, & glycoproteins

hierarchal bundling is a classic organization pattern for what

fibers experiencing tension along a long axis

3 components of scar morphology

flaws, fiber alignment, & fiber size

example of motions in the sagittal plane

flexion & extension

what are some tendons enclosed by

fluid filled synovial sheath

canaliculi

fluid filled, forces supply lacunae with nutrients, viscoelastic activity

law of action & reaction

for every action, there is an equal & opposite reaction whenever an object pushes on another object, it gets pushed back equally hard in the opposite direction

strain

force normalized to deformation

stress

force normalized to the amount of material

air resistance

force of air pushing back on an object

friction

force resisting things sliding over one another like solids, liquids, etc

gravitational force

force that one body exerts on another/refers to the pull of earth on the body

tension

force transmitted through a string or rope (or biological tissue) when it is pulled from either end

work =

force x distance

bones need what

forces

wolffs law

forces present cause shape & if a force is present change will occur

sagittal/longitudinal plane

front & back

cyro-grips

frozen material/dired material behave differently then life tissue

class 1 lever

fulcrum is between the effort & load

holes in the cartilage structure affects what

function

what happens to proteoglycan content after an injury

generally does not recover

how is the transition from the spindle shaped tendon cells to rounded cartilage chondrocytes

gradual

types of non-contact forces

gravitational, electricostratic, magnetic

mechanical advantage of a class 2 lever

greater than 1

mechanical advantage of a class 1 lever

greater than, less than, or equal to 1

what is the purpose of having a fluid filled synovial sheath

greatly reduced friciton

metaphysis

growth zone

proteoglycans hold onto what

h2o

what happens during cyclical loading that leads to fatigue failure in the tendons

h2o can't get back in & will fail at a stress

the more dense -->

handle stress better

4 types of spaces in bone

haversian canal, volkmann's canal, lacunae, & canaliculi

exercise causes what with chondrocytes

helps chondrocytes to produce the matrix

where are contact areas when we are the strongest

high at the joint angles

stiffer spring -->

higher restoring force

parallel fashion -->

higher tensile strength in cartilage

how organized is primary bone

highly

proteoglycans

hold onto water, protein core, side chains containing sugar

simplest kind of spring

hookean spring

what is crucial to understanding biomechanics

how an organism moves & the diversity of locomotion

velocity

how fast & what direction

speed

how fast something is going

what does momentum depend on what

how fast something is going & how much it is going

angular momentum =

i (moment of inertia) times w (angular frequency)

hysteresis

if a viscoelastic material is loaded & unloaded, the unloading curve will not allow for the loading curve

area under the grf curve

impulse

what happens to bone resporation at the insertion site due to disuse

increased

age & cartilage relationship

increased age, decreased cartilage strength

how does exercise increase ligament strength

increased fiber #, collagen content, cross linking, & glycoproteins

why is obesity a risk factor for osteoarthritis

increases the load & could possibly change the chemical composure

what occurs due to the longitudinal folding in the myotendinous junction

increases the surface area contact by 10-20x, sometimes even 50, which transfers the stress from muscle to tendon greatly

intensive property

independent of the size of the system & does not depend on the amount of material

yield & failure region of a non-linear s-s curve

individual fibril begin to fail damage accumulates stiffness is high

where is the myotendinous junction typically located

insertion & origin end of the muscle belly

actin cytoskeleton

inside cell protein actin forms filaments that provide cells with mechanical support & driving forces for movement actin contributes to biological processes such as sensing environmental forces

how are position & motion linked

instantaneously

2 pathways of sensing in cartilage

integrins & actin cytoskeleton

what sized objects are in newtonian mechanics

intermediate sized (biological realm)

how are collagen fibers organized in ligaments

into bundles & oriented between insertions

when an object is at a different position what happens

it has been displaced & a motion has occurred

cartilage models

it is nearly impossible to measure in vivo mechanics

tendon's high tensile stiffness & strength of a tendon is attributed to what

its relatively high collagen content (70-80% dry weight) & its hierarchical organization into linear bundles

units of momentum

kgm/s

2 typed of energy

kinetic & potential

Hooke's law f=

kx

scaring in ligament healing

larger cross-sectional area more material but a lot weaker when evaluated as a material property

what newton's law is mechanical advantage similar to

law 3 - law of action & reaction

newton's 2nd law

law of acceleration

newton's 3rd law

law of action & reaction

newton's 1st law

law of inertia

what 2 factors affect effective mechanical advance

length of the moment arm & mass

how does aging affect the collagen crimp in ligaments

less crimp --> decreased toe region

mechanical advantage of a class 3 lever

less than 1

where are golgi tendon organs

lie within a tendon & close to the myotendinous junction

what has more collagen

ligaments

what human material properties have a toe region

ligaments & tendons

example of spring forces

ligaments/tendons with shock absorption & energy storage

force is required for what type of acceleration

linear

translation is what type of motion

linear

is the function of proteoglycans the same in both cartilage & ligaments

nah

what will be the result of if a tendon is cyclically stretches & allowed to recoil within the range of reversible strain

load deformation measurements form a loop

class 2 lever

load is between the effort & the fulcrum

torsion

loading that results from twisting & can give shear stress magnitude of the stress is dependent on the size & shape of the object in the cross-section

materialas deform in response to what

loads

grip in tendon

location of stress concentration wider clamp variety because they are longer than ligaments cyro-grips

what type of projections do osteocytes have

long projections like neurons

what type of folding of the tendon into the muscle cells occur in the myotendinous junction

longitudinal

stiffness in the toe region

low

tendon has _______ hysteresis

low

how much friction is in the environment of a tendon

low amounts

proteoglycan content in the superficial layer

low content

synovial fluids acts as a what

lubricant

scalars have what

magnitude

increased mineralization -->

make bone stronger but make them more likely to break

osteocytes

mature osteoblasts (ones that get trapped in the bone)

disuse of cartilage reduced what

mechanical stimulation, reduced nourishment to the cells, & a reduction in proteoglycan synthesis

periosteum

membrane outside (source of stem cells)

which zone of cartilage is the most metabolically active

middle

2 types of % of dry weight in bone

mineral & organic

is bone static

nah, will break down if they aren't used

what happens to momentum if there is a perfect collision (no energy less due to friction, air resistance, heat, etc)

momentum is conserved

proteoglycan content of middle zone

more & less water than the superficial zone

why are tendons better at resisting tensile forces than ligaments

more elastin than ligaments

stress fracture

more osteoclast activity than osteoblast

more extensive property -->

more property

what does the increased cross linking & collagen content cause in adapting to aging in ligaments

more small gibers, decreased water content, decreased ultimate stress

what does secondary bone have that primary has less of

more space for vascular structures for nutrients

dishes causes what in the bone

more spaces in the bone

what would happen if bone just directly attached to ligaments without fibrocartilage

more stress

combined loads

most loading is a combination of different mechanics

what type of fibers are the collagen in ligaments

mostly 1

collagen

mostly type 2 fibers long ropes of protein

what does a force cause

motion

y parameter of kinematic equations

motion

what does newton's law of motion explain

motion & how forces result in movement

examples of kinetic energy

motion, heat, sound

how to adjust the length of a moment arm

move the center of mass / limb position

how does scaring of the ligament impacts viscoelastic properties

much inferior & h2o leaks out

fatigue failure is unique to what 2 material properties in the body

muscle & tendons

example of tension

muscle pulling on a tendon

golgi tendon organs are mechanoreceptors that monitor what

muscle tension

does kinematics involve force

nah

centrifugal force

not a real force rather the apparent force that occurs when you exert a centripetal force

end effect for tendons

not as effective as in ligaments

fiber size & scar morphology

not normal at 40 weeks smaller than native ligament

tensile stress

occurs as a result of a force that is pulling apart an object

shear force

occurs perpendicular to tension or compression & slides molecules of the object past each other

cancellous bone

oriented primarily in the direction of the forces applies to the bone organized to withstand mechanical loads while minimizing weight of the bone

excessive loading can lead to what

osteoarthritis

lacunae

osteocytes & creates spaces when trapped

1-2.5 standard deviation below average

osteopenia

>2.5 standard deviation below average

osteoporosis

what are cement lines in secondary bone

outside edge hardened & is the joint between 2 bone types

external tendon

outside muscle cord

tendonitis

overuse equivalent to the stress

superficial layer are arranged how

parallel

where do the majority of collagen fibers lie

parallel to the long axis of the tendon

what are several fascicular bundles surrounded by

paratenon (outmost tendon sheath)

units of poisson ration

pascals

units of stress

pascals

the deep collagen fibers of the tendon do what

penetrate the periosteum & attach directly into the bone

how are fibers arranged in the deep zone

perpendicular

anisotropy

physical or mechanical proper of a material which allows it to change or assume difference

examples of biomechanics application

physical therapy, prosthetics, joint replacement, car crash, ergometry, & sports performance

what is secondary bone very much like

primary osteons

viscoelastic properties

property of material exhibit both viscous & elastic characteristics when undergoing deformation

ligament cross-sectional area

proposed decrease csa with stretch (poisson ration) difficult to declare true csa

momentum

quantity of motion of a moving body, as a mass is in motion

3 types of mechanics

quantum, relativistic, & newtonian

torque =

r (distance from center of rotation) times F (force)

osteotendinous junction components in cortical bone

relative high stress concentration, superficial fibers blend into periosteum, & deep fibers penetrate bone

to transmit force from muscle to bone what does the tendon need to be

relatively stiff & strong in tension but be able resist deformation

cartilage has a limited ability to what

remodel

viscous material

resist shear flow & strain linearly with time when stress is applied

secondary bone is the product of what

respiration of previous bone

statics has constant what

rest or acceleration

tenosynovitis

rom swelling mechanism

example of motions in the transverse plane

rotation

3 planes

sagittal, frontal, transverse

example of a shear force

scissors

example of a class 1 lever

seesaw

the myotendinous may be stronger in what than in tension

shear

what mechanical property of cartilage is not fully understood as it is hard to test

shear

what stress are most materials are weakest with

shear

types of stress

shear, compression, shear, bending, torsion, combined, & strain

2 components of a stiff tendon

short tendon & big cross-sectional area compared to the muscle ration

frontal/coronal plane

side to side

interns

signaling proteins tied to the membrane that regulate growth, proliferation, migration, signaling, & cytokine activation & release

levers

simple machines that consist of a rigid beam or rod that pivots around a fulcrum

why it is crucial to have trupoclalegn & microbial helices

since they have different direction helices it keeps the material from unwinding when loading

adaptation from exercise in tendons are what

site specific

example of static mechanics

sitting

what do chondrocytes mimic

skeletal development

shear properties are very what

slippery

epiligaments

smaller collagen fibrils, oriented more randomly very cellular protection/friction reduction support nerves & blood vessels

why must axial vectors all be parallel to the axis of rotation

so only the magnitudes of the vectors are necessary

cortical bone

solid, dense material composing the walls of diaphysis & external surface of bone & external surfaces of bone

relatively flat plastic region

some fibers stretch more considerable yield region in which tendon deformation is accompanied by very little increase in stress fairly high ultimate strength

example of dynamic mechanics

someone sprinting off the line

what type of element is associated to motion

spatiotemporal

what are golgi tendon organs comprised of

specialized nerve ending that air in a series with the contractile proteins of the muscle

golgi tenon organ summary

specialized nerve endings found near myotendinous junction in series with muscle fibers are compressed when muscle contracts have highly myelinated afferent neurons relay info back to the central nervous system about contraction levels in the muscle cause inhibition of contraction

what is a class 3 lever also called

speed multiplier lever

k

spring constant

hooke's law describes

springs

why is the type of loading with cartilage important

static loading --> bad intermittent loading --> good fluid flow

example of isotropy

steel

elastic material

strain when stretched & immediately return to their original state once the stress is removed

ratio between compact vs spongey bone determines the balance between what

strength & mass

end effects

stress concentration at point of grip can result in inaccurate point of measurement

stress relaxation

stress will be reduced or will relax under a constant deformation

young modulus (E) =

stress/strain

material properties of bone

structural properties of bone refer to the organization of compact or cortical bone & the spongey or trabecular bone

what happens to proteoglycans when one ages

structure changes sugar is shorter & has less water content there is a shorter core & side chain

dynamics

study of systems in motion with acceleration

statics

study of systems that are in a constant state of motion, whether at rest with no motion or moving at a constant velocity without acceleration

kinetics

study of the forces associated with motion of a body/forces acting on an object

objects excluded in mechanics

subatomic, objects moving at the speed of light

what zone are tensile properties are higher

superficial

what of the tendon blend in with the periosteum in cancellous bone

superficial collagen fibers

4 layers of articular cartilage

superficial, middle, deep, calcified

slow strains are more likely to what

tear ligament

what has more elastin

tendon

3 types of tendon injuries

tendon adhesions, tendonitis, & tenosynovitis

what are visible at the fascicular level of tendon organization that are longitudinally aligned among fibre bundles

tendon cells

tendon healing

tendon is somewhat vascular however the healing process won't be complete

exercise can increase what in tendons

tendon size & collagen content

what 2 properties are often loaded with pure tension

tendons & ligamanets

ligaments have a hierarchical structure arranged between insertions to resist what

tensile forces

collagen on the outside of the cartilage is loaded in what

tension

compression force is opposite of what stress

tension

golgi afferent synapse inhibit what during isometric contraction

the alpha motion neurons of the corresponding muscle

what does the difference between the 2 curves in hysteresis represent

the amount of energy that is dissipated or lost during loading

poisson ration

the amount of material in an object is fixed thus if an object is stretched it will get thinner or if an object is compressed it will bulge out

endosteum

the ct membrane lining medullary cavity (inside)

how do chondrocytes receive nourishment

the diffusion

synovial fluid permits what

the diffusion of gasses, nutrients, & waste

what do material properties often vary in

the direction in the the material in which they are measured (referred to as anisotropy)

mechanical advantage

the efficiency of a lever

why is the mechanical advantage of a class 3 lever less than 1

the effort arm is smaller than the load arm

epiphyses

the end part of a long bone, initially growing separately from the shaft (secondary ossification)

normal force

the force acting perpendicular to the surface on which an object sits

spring forces

the force exerted by a stretch or a compressed spring or any object attached to it

elastic region

the linear region where the material can deform without resulting in permanent change

why is the mechanical advantage of a class 2 lever greater than 1

the load arm is smaller than the effort arm

young modulus can be tested in multiple directions depending on what

the material

ultimate strength

the max amount of s & s the material can sustain prior to breaking

biomechanics

the mechanics of biological objects & physical worlds interacting

what makes the tropocollagen molecules enhance the tensile properties of the tendons

the molecules in the heavily cross linked regions of the fibers are crystallized

yield point

the point where material cannot revert to the original form

power

the rate at which work is done (energy per unit of time)

what defines a lever

the relationship between the fulcrum, effort, & load

electrostatic force

the repulsive/attractive interaction between any 2 charged bodies

for adhesive joints it is desirable to maximize what

the shear component of loading

young modulus

the slope of the line approaching the yield point

golgi afferent synapse with the interneurons of where

the spinal cord

mechanics

the study of the motion of objects

what does each golgi tendon organ connect to

the tendinous fascicles associated with approx 10 muscle fibers

for adhesive joints it is desirable to minimize what

the tensile component

what 2 things does the lever change

the torque exerted & the distance moved by an object

failure strength

the value in which the material "breaks"

things get heavier faster than what

they get stronger

what happens to ligaments at insertion from disuse

they will fail

applied forces

thing push or pulling on another object

evolutionary advantage of proximally distributed le mass

things that are good runners tend to move mass more proximally in the limbs

how do some tendon cells get nutrients

through diffusion partially inside the synovial sheath

x parameter of kinematic equations

time

why does bone need to be sufficiently rigid

to provide the necessary support & force transfer but also capable of deforming enough to absorb the energy of an impact before breaking

afferent

to the CNS

zero strain position

toe region make it difficult to know where the strain begins

components of a non-linear s-s curve for ligaments

toe region, linear plastic region, & relatively flat plastic region

transverse plane

top & bottom

bending

torsion on 1 side & compression on the other very common loading condition

what is cancellous bone formed by

trabeuclae (thin bony spicules)

osteotendinous junction

transition from tendon to fibrocartilaginous tissue

middle zone arrangement

transitional zone with more random arrangement of fibers

functions of tendons

transmit force from muscle to bone, apply force to a relatively small content surface, & storage of elastic energy & return

functions of cartilage

transmit forces across joint, muscles pulling to create movement, distribute forces to minimize stress concentrations, & provide low friction surface

purpose of the structure of the calcified zone

transmit forces safely across the joint

primary role of a tendon

transmit the force of it associated muscle to bine

tendon adhesions

trigger finger/frozen

most basic unit of collagen

tropocollagen

tendon hierarchical structure

tropocollagen --> microfibrils --> sub fibrils --> fibrils --> fibres --> fibre bundles

difference between tropocollagen helix & microfibril helix

tropocollagen has a left hand helix & microfibrils have a right hand helix

example of a class 3 lever

tweezers

why is an accelerating system unbalanced

unequal forces acting on the body

isotropy

uniform in all orientations

linear elastic region of tendon

used to calculate young modulus

what does the calcified zone have more than the deep zone

vascularization

what sized objects are in relativistic mechanics

very large (stars & blackholes)

what sized objects are in quantum mechanics

very small (atoms & subatomic particles)

vf =

vi + at

4 main structural components to ligaments

water, collagen, proteoglycans, elastin

what does a random orientation of collagen fibers cause

weakness

example of a class 2 lever

wheelbarrow

centripetal force

when an object is moving around a circle, the linear velocity is constantly changing directions but not magnitude

when is crimping 1st apparent in tendons

when fibre aggregate to form fibre bundles

when is a lever balanced

when torque 1 = torque 2

example of stress relaxation

when you bend over, your flexor & extension muscles cannot both be fixed

extensive property

whose magnitude is additive for subsystems

power =

work/time

what axis is strain on

x

cos =

x/r

what axis is stress on

y

sin =

y/r

tan =

y/x

can the young modulus revert back

ye

does helical interweaving vary among structural levels

ye

does kinetics involve force

ye

does the transition within the osteotendinous junction differ in cortical & cancellous bone

ye

is cartilage mechanosenstitive

ye

can bone deform

yes since it has water content in it which makes it viscoelastic

can you stretch the toe region of a graph

yes, it is easy to stretch initially due to the crimp pattern

example of a centrifugal force

you feel like you're getting thrown off a ride

the variation of the calcified zone in a cellular environment is thought ti influence what

zonal changes rather than a discrepancy between cells

what happens in the superficial layer

zone is permeable & though to contribute ute to signaling successive zones


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