Ex 2 Flashcards
What component of CT determines the type of tissue and its functions?
Fibrous components
What are the two components of CT?
Cells & ECM
What are the components of ECM?
- Fibrillar: fibrous component
- Interfibrillar: Ground substance (PG & GAG)
- Water
What kind of CT does the following?
- multidirectional fiber orientation
- made up of collagen and elastic fibers
- allows for a lot of motion
Components of loose irregular CT
Where is loose (irregular) CT found?
between muscle, nerves, vessels and superficial fascia
Components of dense irregular CT
- fibers are arranged in layers
- many fibers, few cells
- good to resist tension
Where is dense irregular CT located?
in muscle, nerve sheaths, joint capsule, and dermis
Components of adipose tissue (also irregular CT)
- fat cells encased in fibrous tissue
- good for shock absorption and maintaining structural barriers
Where is adipose tissue located?
bone marrow and subcutaneous tissue
Components of regular CT
- primarily made of collagen fibers
- organized into bundles
resist tension forces applied parallel to the fiber orientation
Where is regular CT located?
tendons, ligaments, deep fascia/aponeuroses
What are the 4 resident cells in CT?
Fibroblasts
Chondroblasts: primary cartilage cell
Osteoblasts: primary bone cell
Mesenchymal (Stem cells)
What are the circulating cells?
Lymphocytes
Macrophages
Functions of fibroblasts?
- produces ECM
- important for wound repair
- creates bond to collagen fibers
- always around
Lymphocytes function?
- increase in number after tissue is injured
- only come at certain times - originates in bone marrow and is passed to the tissue via the lymphatic system
Macrophages function?
- responsible for phagocytosis
- immunologic
- usually fixed to fibers, but will circulate in response to inflammation
Functions of mesenchymal (stem) cells? Location?
- primitive, undifferentiated cell which means they become whatever is needed
- precursor to chondrocytes, osteocytes, etc.
- located along blood vessels
What are fibers?
proteins that provide the supporting framework to tissue
What cell creates the ECM?
Fibroblasts
What is tropocollagen molecule?
developed from an alpha procollagen (polypeptide) chain and twisted into a triple helix
The tropocollagen molecule is synthesized through the endoplasmic reticulum of _________
Fibroblasts
Tropocollagen molecules attract to one another forming a _______. These then form a fascicle and the fascicles coming to form a single fiber.
Fibril
What cells make collagen fibers?
fibroblasts!!!
- no healthy fibroblasts, no healthy CT
What is Type I collagen?
most widely distributed throughout body
- more tensile
Where can you find Type II collagen?
most forms of cartilage
- hyaline, menisci, etc.
- more compressive
What forms elastic fibers and what are they?
- formed by fibroblasts and some smooth muscle cells
- highly cross linked protein that can stretch to several times its original length and return to original size after force is removed
Tendons and ligaments are primarily ____ except _____/.
- collagen, ligamenta flava
What is ground substance made up of?
PG and glycoproteins
Components of PGs?
- turn water into gel like substance because they draw water in
- consist of polysaccharide chains attached to a core protein
What are the types of PGs?
- agggrecan
- versican
- aggregating (creates water bed)
- biglycan
- decorin
- non-aggregating
What makes up PGs?
GAGs and core protein
What determines how hydrated the ECM is?
the percent of PGs in the interfibrillar component
What charge to GAG chains have and and how does it affect the flow of water?
GAG chains are negatively charged so they attract positively charged ions.
- as water flows, it creates a tensile stress on the collagen network and the collagen resists this pressure and contains the swelling of water
If you wanted to resist a great deal of compression, would you want a few or a lot of GAGs?
what about tensile forces?
- a lot of GAGs
What two types of PGs pull more water into the GAGs?
aggrecan
aggregate
What is the role of glycoproteins?
- adhere PGs to collagen and interact between adjacent CT cells
Types of Glycoproteins?
Fibronectin
laminin
link proteins
What are the functions of tendons?
- attach muscle to bone
- transmit loads form the muscle to bone
- allow muscle belly to remain at an optimal distance form the joint that it acts on
What are the functions of ligaments?
- attach bone to bone
- addresses mechanical stability of the joint
- has passive force and does not create torque - guides joint motion
- prevents excessive joint displacement
What type of collagen are tendons and ligaments made of?
Type 1
What are the other properties of tendons and ligaments?
- cross links are formed between collagen molecules and essential to aggregation at fibril level
How are tendon fibers arranged and what is the importance of it? How much elastin do tendons have?
- orderly, run parallel in primarily in one direction
- important to be arranged this way to withstand high unidirectional loads during regular activity
- barely any elastin
How are ligament fibers arranged and what is the importance of it? How much is the elastin component?
- fibers are not completely parallel but are closely interlaced with one another
- can withstand loads primarily in one direction but can withstand smaller loads in other directions
- scarce amount of elastin (exception ligamenta lava)
What kind of CT surrounds tendons and ligaments?
loose areolar CT
In tendons, what is the function of loose CT?
Areolar CT forms a sheath to protect the tendon and enhances gliding
What is the epitenon, its function, and where is it found?
Epitenon is a synovial layer just below the loose CT that surrounds the entire tendon.
- this is found in tendons that are subject to high levels of friction (like fingers)
- Epitenon can surround several fiber bundles –> endotendon
What is the tendo-osseus junction?
Where collagen fibers of the epitenon continue into the bone and become continuous with the periosteum
What is enthuses?
fibrocartilaginous and fibrous
- this is all the notes say, no idea what this means
What happens at fibrocartilaginous zone 1?
At the end of zone 1, the collagen fibers intermesh with unmineralized fibrocartilage
What happens at fibrocartilaginous zone 2?
unmineralized fibrocartilage eventually becomes mineralized fibrocartilage
(unmineralized fibrocartilage is zone 2)
(mineralized fibrocartilage zone 3)
What happens at fibrocartilaginous zone 3?
mineralized fibrocartilage merges into cortical bone (cortical bone is zone 4)
What are the basic mechanical principles of tendons and ligaments?
Stress and Strain
Definition of stress
- internal force per unit fo cross sectional area of the ligament or tendon
- units are Nm2 pascal
proportional increase in length of the ligament or tendon form its original length in response to externally applied loads
- units are
Definition of strain
What is the toe region in the stress/strain curve
just enough force to line up fibers but they have not extended yet
What is the elastic region of the stress/strain curve
- linear relationship
- change here is reversible
- slope
What is the plastic region of the stress/strain curve
- continued elongation, length is actually changing here
- micro tears, might not be able to return to its original shape
- good to create flexibility
- if our muscles are really tight, we want the micro tears where we do stretching
What is the ultimate failure point of the stress/strain curve
not enough fibers to do the job so the collagen breaks
Do tendons or ligaments have a bigger toe region and why?
ligaments have a bigger toe region
what are tendon and ligament strength determined by?
size and shape of the ligament or tendon
(number and length of fibers)
- tendons are more stiff and have a straighter slope
- pls look at these diagrams in the book
Ligaments on the stress/strain curve
- thicker ligaments take more force to failure
- length of ligaments and tendons are not bigger or wider but they change the stress strain curve a lot
- longer fibers with the same amount of force = very stiff
What is viscoelasticity?
all CT have viscoelasticity
- includes time and rate dependent properties
What are time dependent properties?
When a viscoelastic material is subjected to either a constant compressive or tensile load, the material deforms and continues to deform over a finite length of time, even If the load remains constant
What is stress relaxation?
loaded is halted safely below the linear region of the stress/strain curve and these strain is kept constant over an extended period of time
- pls look at pics in notes
Role of creep in stress-relaxation
- if we load creep moderately over a long period of time (constant stress), we will continue to get deformation
- no micro tearing, but does elongate over time
- as therapists, we use creep
EX in life: dresser making indents in carpet
EX as PTs: hold stretch for 30 seconds
What is an example of a rate dependent property?
stiffness
Definition of rate dependent properties
viscoelastic materials respond differently to different rates of loading
- when loaded rapidly, they exhibit greater resistance to deformation than if they were loaded more slowly
- this would be seen as a steeper linear portion of the stress/strain curve
What happens to ligaments and tendons with higher strain rates?
w/higher strain rates, tendons and ligaments in isolation store more energy = requiring more force to rupture = undergo greater elongation
What is strain rate?
if a force is loaded rapidly, a larger peak force can be applied than if the force was loaded slowly
- creep will not occur if a force is loaded rapidly
What factors affect the biomechanics properties of ligaments and tendons?
- injury: less stable
- immobilization: 50% decrease in strength after 8 weeks of mobilization
- pregnancy: women who are pregnant get loose all over their body, and could become hurt due to everything relaxing
Functions of bone?
support protect internal organs produce RBC facilitate movement store minerals
What is the diaphysis and its components?
shaft of bone
- compact bone
- medullary cavity
- yellow bone marrow (in cavity)
What is the metaphysis?
eipsphyseal line/growth plate
What is the epiphysis and its components?
- ends of bone
- compact and spongy bone
- red bone marrow
What are the organic components of the ECM in bone?
- Fiber (Type 1 collagen), provides some flexibility/tensile strength
- Chondroitin sulfate
What are the organic components of the ECM in bone?
- organic substance: 25%
- Fiber (Type 1 collagen), provides some flexibility/tensile strength
- Chondroitin sulfate
What are the inorganic components of the ECM in bone?
- minerals or “bone salts”
- Calcium phosphate + Calcium carbonate = hydroxyapatite
- Magnesium hydroxide, fluoride, sulfate, etc.
- hardest of all CT in body because it has the highest inorganic tissue
What gives bone compressive strength?
inorganic component of ECM
- 50%
What cells are in bone?
fibroblasts, osteoblasts, osteocytes, osteoclasts
Osteoblasts function and location?
- form new bone
- synthesize and secrete collagen matrix and calcium salts
- L: epiphyseal plate, endosteum, periosteum
Osteocytes function and location?
- secrete enzymes to maintain mineral concentration
- maintain bone tissue and produce collagen and other ECM
- L: entrapped in matrix
Osteoclasts function and location?
- reabsorption of bone
- L: bone surfaces, injury site
Osteogenic cells function and location?
- Stem cells fo bone. they differentiate into osteoblasts
- L: deep periosteum and bone marrow
What is cortical bone
- dense and compact bone
- organized in concentric lamellar layers
- distinct line in interfibrillar component at periphery separate GAGs
- high elastic modulus
What is cancellous (spongy) bone
- formed by trabeculae
- trabeculae are laid down in response to stresses placed on bone
- uniformly distributes contact stresses and absorbs loads
- anisotropic
- blood vessels run along trabeculae
- covered by a thin layer of compact bone
- spongy bone can withstand forces from different directions but not with the same amount of force
What is woven bone
- collagen fibers are irregularly arranged to form a pattern of alternating coarse and fine fibers
- forms rapidly., if ou have an injury, a callus forms, and the new bone that forms over it is woven bone which eventually matures
how is lamellar bone organized
in parallel layers
- what we see in human skeleton
where is the periosteum and its 2 layers?
- covers entire bone surface EXCEPT for the articulate surface, bc thats covered by articular cartilage
- outer fibrous layer, inner osteogenic layer
Components and function of the outer fibrous layer of periosteum
- contains nerves, blood vessels, lymph vessels
- attachment site for tendons/ligaments
Components and function of the inner osteogenic layer of periosteum
- reservoir for growth repair
- contains fibroblasts, stem cells, and osteoblasts
- damage to the periosteum decreases the healing capacity, bc damage usually decreases the blood supply too
What happens in the endosteum and where is it located?
- lines the medullary canal
- where bone growth, repair, and remodeling occurs
- has osteoblasts, osteoclasts, and osteogenic cells
Where is the blood and nerve supply to bone?
- nutrient arteries pass through the nutrient foramen in compact bone
- veins and lymph vessels run with arteries
Where is the blood and nutrient supply in compact bone?
vessels run up and down through the Haversian canals
Where is the blood and nutrient supply in cancellous bone?
blood vessels are in the periosteum and blood in the marrow cavities
What type of loads can bone withstand
tension, compression, shear, torsion, and combined loading
- combined loading is compression on the medial side and tension on the lateral side
- can resist compression more than shear or tension, can handle shear the least
What is Wolff’s Law?
bone remodels in response to external stresses such as weight bearing and muscular tension
What are the viscoelastic properties of cortical bone?
cortical bone is stiffer than cancellous bone so it can withstand a greater amount of stress but less strain than cancellous bone
cancellous bone can sustain ____ strain before failing
HIGH.
high strain, less stress
Cortical bone fails if strain is greater than ____
2%
higher stress, less strain
stress and strain in bone?
EX of stress in bone: be body weight
EX of strain in bone: amount that femur bends (deformation)
- strain is an effect of stress
Effects of high loading (quick loading) bones
- rate changes
high (quick) loads over a short time will produce HIGH stress
- greater load before fracturing and more stiffness
Effects of low/slow loading in bones?
- rate changes
slow loads over a long time will produce HIGH strain
- not as stiff or strong, fractures occur under slow loads
Effects of increased repetitions with bone?
- less stiffness
- more deformation
- lower load to failure
What is bone fatigue?
repeated loading can cause permeant strain and lead to bone failure
Effects of aging on bone
- decreased bone stiffness
- decreased load to failure
- at age 30, bone density starts to decline
- in postmenopausal women, this is accelerated
osteopenia
Effects of injury on cortical bone healing
- inflammation
- Soft callus: blood clot replaced by fibrous tissue/cartilage
- Hard callus: new bone (woven) is initially deposited on either side of the fracture site, then proceeds to gap, eventually forming a collar
- Remodelling: continued bone formation, more compact (lamellar)
- In adults, this takes 6-8 weeks to occur and even longer in older adults
Effects of injury on cancellous bone healing
- little or no callus formation
- healing occurs via direct osteoblastic activity (creeping substitution)
- little bit of stress helps this process
Effects of immobilization on bone
- bone is reabsorbed but not produced
- decreased collagen synthesis and mineral content, increases regional osteopenia
- Weakened connections of ligaments and tendons to bone
- wt bearing important because stress helps to create the new bone so you want to do it ASAP
- if you have plates and screws, there will be less collagen synthesis and less mineral content and a little bit of osteopenia
Functions of articular cartilage
- located in between bones
- shock absorber
- distributes loads over a bigger area bc of the deformation properties it has
- provides lubrication which allows movement with low friction
Structure of articular cartilage
- specialized form of hyaline cartilage
- appears smooth but is covered by pits elevations and ridges
- synovial fluid goes into the pits and ridges to help smooth joints
- chondrocytes, collagen, PG, water
Function of chondrocytes in articular cartilage
produces and maintains the organic components of AC such as collagen, PG, and glycoproteins
- responds to mechanical and chemical stemuli such as stem cells
Function of PG in articular cartilage?
bring water in
- mutual repulsion
- compression increases repulsive force and compressive stiffness
What type of collagen is in articular cartilage?
primarily Type II bc more resistant to compression
- provides framework and tensile strength
function of glycoproteins in AC
large molecules that secure the chondrocytes within the fibrous network
- fibronectin, laminin, chondronectin
What is the most abundant component of AC?
water
- most concentrated near the surface and decreased linearly with increasing depth
- when tissue is loaded, up to 70% of water can be moved
- AC does not easily allow fluid to move thru
What happens to cartilage when water increases?
- as water Increases, cartilage becomes less stiff and more permeable
What is the superficial/tangenitial zone in AC?
- densely packed fibers woven parallel to articular surface
- resist shearing forces on the surface
- decrease friction by distributing force
What is the middle zone in AC
- randomly oriented and dispersed fibers far apart
- forms network that surrounds the chondrocytes
- absorbs forces and permits deformation
What is the deep zone in AC
- fibers in tightly packed bundles
- Tidemark: between AC and calcified cartilage beneath it. purpose is to form an interlocking root system that anchors the cartilage to the underlying bone
Properties of AC
- avascular and aneural
- if injured above tidemark, there is less bleeding and teh cartilage cant heal itself well
- deep injuries heal better
What is subchondral bone
align matrix configuration
- counteracts the line of application of the average load to the joint
How does AC get its nutrition
synovial fluid via compression and decompression of the cartilage surface
- motion of the joint is essential for cartilage nutrition
Where is permeability the highest and lowest in AC?
- highly porous but not permeable
- highest: near joint line
- lowest: near deep zone
As AC is compressed, permeability _____
decreases
- fluid content of cartilage is sent out though pores in the outermost layer
- fluid flows back into the cartilage when compression is removed
As the joint is loaded, most of the fluid that corosses the articular surface comes from ____
cartilage closest to joint surface
Functions and components of synovial fluid
- exchanges metabolites
- contains libricin and hyaluronic acid
Why is AC different than other cartilage?
Bc AC is a compressive force
Effects of rapid loading in AC?
- no time for fluid to flow out, pressure comes from teh interstitial fluid instead of the solid matrix, supports a significant portion of the load
Effects of slow loading in AC?
fluid pressure decreases and stress in the solid matrix increases
- water can escape a little bit and the ECM supports the load
Creep response in AC
- AC deforms under constant load
- displacement of AC is rapid initially so there is. large flow out of the cartilage
- as the rate of displacement slows, fluid flow slows
- at equilibrium displacement is constant and fluid flow has stopped
- takes 4-16 hours to reach equilibrium
Stress-relaxation response in AC
- during compression, stress increases continuously until a specific deformation is reached then stress decays until equilibrium is reached
- stress rise: associated with fluid leaving
- stress relaxation: fluid redistributing within the porous solid matrix
What resists tension in AC and what is the function
collagen superficial tangential zone
- provides joint cartilage with tough wear resistant protective skin
What is fluid film in AC?
thin layer of freestanding lubricant between sliding surfaces that decreases surface to surface contact area
what is hydronamic in AC?
occurs when rigid bearing surfaces that are NOT parallel and separated by a fluid film slide tangentially in relation to each other
What is squeeze film in AC?
occurs when wt bearing surfaces are moving perpendicularly towards each other.
- viscosity of the fluid in the gap between the surfaces produces pressure that forces the lubricant out
- only in compression
what is weeping in AC
joint load is supported by hydrostatic pressure of the synovial fluid escaping form the cartilage
what is boosted lubrication in AC
as a load is applied, synovial fluid is trapped in the cartilage toward the subchondral bone at the point of contact
What causes degeneration of AC
- increased stress concentration
- wear and tear
- high load over extended period of time
- chemical insults
- metabolic factors
What are histological changes in AC?
- increased water content secondary to freeing of GAGs neg bonds
- loss of PGs = decreased mechanical props
- PGs less dense bt fibers = poor matrix support
What is interfacial wear in AC?
- Adhesive: fragments stick and pull away form the surface
- Abrasive: soft material scraped by harder material
What is fatigue wear in AC?
accumulation of microscopic damage under repetitive stresses
What is the superficial response of AC to trauma?
- superior most aspect is sheared off
- inflammatory response of articular cartilage Is zero
- a superficial laceration allows for minimal healing
What is the response of AC to a deep cartilage lesion or an “osteochondral defect”?
- bleeding in subchondral bone produces hematoma that becomes organized and invaded by granulation tissue
- Fasciculation: flakes of cartilage break away into the joint space
- Fibrillation: cracks in AC, which decreases the energy being absorbed
What are the effects of immobilization on AC?
- Decreased PG aggregation
- Increased water concentration
What is the main source of stability in our body?
muscles
- losing mm at one segment will significantly alter the function
What are the types of tissue in muscle?
- Contractile (mm tissue)
- non contractile (CT)
What are the properties of muscle?
- Contractility: create tension
- Irritabilitiy: responds to stimulus
- Extensibility: stretch if lengthened
- Elastic: returns to resting length after being stretched
What is a sarcolemma
each m fiber is an individual cell enclosed in a membrane
Fasciculi
group of muscle cells (sarcolemma)
- referred to as a m fiber
- one m made up of many fasciculi
Muscle fiber contents?
- cytoplasm
- myofibrils: part of cytoplasm, contractile in nature
- workhorse - non myofibrils, ribosomes, glycogen and mitochondria
- needed for nutrition
What are myofilaments?
components of myofibrils
- actin and myosin binding causing m cxn
What binding sights are on actin
troponin and tropomyosin
- actin is thin filaments
Function of myosin?
heads allow movement for binding site for attachment of actin
- myosin is thick filament
Z lines
boundaries of sarcomeres where actin and myosin bind
sarcomere
portion of the myofibril bt z lines
A band
area that covers the entire myosin myofibril and part of the actin myofibril
H zone
area of the A band covering myosin where no actin overlaps
M band
wide middle portion of myosin
I band
Only actin
Crossbridging?
AP triggers release of Ca, troponin and tropomysion receptor site exposed, actin and myosin connect forming a CB
- CB allows myosin to pull on the actin
What happens in concentric contraction (shortening)?
- sliding of myofilaments that shorten start at the distance between them
- sarcomeres are smaller
- actin are closer together
What happens in an eccentric contraction (lengthening)?
- actin are spread apart
- distance has not changed but the loading has to be more open (or condensed)
what are the functional units of muscle?
- alpha MN
- Axon
- MEP
what is function of an alpha MN in m
nerve cell that delivers the stimulus found in the anterior horn of the spinal cord
what is the function of an axon in m
extends from the nerve cell and carries the stimulus to end branches which attach to muscle fibers
Function of MEP
close to sarcolemma
- site where axon branches terminate
all fibers innervated by one axon are part of ____
one motor unit
what is a motor unit and what kind is recruited first? Why?
cell body axon and all of the fibers attach to it
- small motor units have fewer primary fibers and they are recruited first
- recruited first because they require less work and energy so it is efficient
What is the function of the SR?
stores Ca in channels between myofibrils
What is the order of firing?
- Small m then large m
- all muscles have a mix of large and small MU
Type I slow twitch oxidative fibers
- slow cxn time
- slow to fatigue
- small MU size
- produces little tension
- best for prolonged low intensity work
Type IIA fast twitch oxidative glycolytic
- fast cxn time
- intermediate to fatigue
- intermediate MU size
- produces moderate tension
Type IIB fast twitch glycolytic
- fast cxn time
- fast to fatigue
- large MU size
- produce large amount of tension
- best for high intensity burst activity
Why is the length of m fibers important?
longer fibers can shorten a greater distance and often have a greater ROM
Examples and functions of parallel m fibers?
- strap, fusiform, rhomboidal, triangular
- long fibers run parallel to mm long axis
- primarily for ROM
- strap mm greater for ROM
Examples and functions of oblique m fibers?
- unipennate, bipennate, multipennate
- shorter fibers but there are more of them
- primary function for short motions and stability
- they have a center tendon
- bipennate good for strength
- lumbricals and inerossei look like bipennate
Endomysium
CT surrounding sarcolemma
Perimysium
surrounds fasciculi
Epimysium
surrounds entire m, continuous w endo and peri
continuations of epimysium for tendons which attach to bone via _____
sharpie fibers
all CT in m is interconnected which constitutes the _____ of a muscle
passive elastic component
What is the parallel elastic component of m?
- all CT surrounding the m, its fibers & sarcolemma
- when the m lengthens or shortens, these structures do the same in parallel
What is the series elastic component of m?
- applies to tendons
- works in a series with the contractile component by “taking up slack”
What is muscle function?
m ability to develop tension and exert a force
What is active tension?
tension developed by the contractile element of a muscle that is initiated by CBing.
- when active tension stops, sarcomere length and passive tension increase
Depends on:
- frequency of MU firing
- # and size of MU
- # of CB
- Crossectinal area (greater area = greater tension)
What is passive tension?
tension developed by non contractile elements of m
which is parallel CT
- CT structures add to active tension or become slack during active tension
- passive tension increases as active tension decreases
What is total tension
the total tension a m can develop during a cxn is:
- Total Tension = active tension + passive tension
- speed and type of contraction effects total tension development
pls look at pics in notes
What is the Length-Tension relationship in m?
direct relationship between tension development and length of the muscle
- eccentric gives greater amount of tension for force
Optimal length
length when a m is capable of developing max tension
- max # of CB can be formed here
- m is slightly lengthened
what state is a muscle in when it is close to optimal?
Resting length of a detached muscle is close to optimal and is a little longer than when it is attached
Overlengthed m
actin and myosin too far apart but passive elastic tension in parallel component can be increased
Shortened m
distance between the Z bands is decreased and filaments overlap resulting in
- max # of CB already formed and no additional CB can be formed to further increase the shortening/tension
When a muscle is activated, whether there is or is not a length change depends on what?
- magnitude of the torque produced by the muscle relative to the magnitude of the torque produced due to load
What is the torque in an isometric cxn?
- Tm/TL = 1
- no motion
- no length change
Tm = TL
what is the torque in a concentric m cxn?
Tm/TL > 1
- motion
- m shortens
- Tm > TL
what is the torque in a eccentric cxn?
Tm/TL < 1
- motion
- m lengthens
- TM < TL
the amount of torque that is exerted during contraction, is the GREATEST for what type of cxn? Why?
Eccentric
- bc active and passive CT
- if you lower an eccentric motion quickly you get more tension
- eccentrics create more tension the faster you go
the amount of torque that is exerted during contraction, is the LEAST for what type of cxn? Why?
Concentric
- bc it is optimal for CB
the amount of torque that is exerted during contraction, is the WEAKEST for what type of cxn? Why?
Isometric cxn
- iso is easier to do than eccentric
What type of contraction produces more force and tension than a concentric contraction?
A resisted isometric cxn
Does a faster contraction create the same amount of tension as a slow one?
No bc in fast contraction you compensate and recruit other strategies
What is the speed of cxn?
rate that CB forms
What is the speed of cxn in an isometric cxn? what happens to tension?
speed is 0 and there is a mild increase in tension
What is the speed of cxn in a concentric cxn? what happens to tension?
shortening speed increases and tension decreases
What is the speed of cxn in an eccentric cxn? What happens to tension?
speed of lengthening increases and tension increase
What is active insufficiency?
- poor ability to develop tension
- caused by an active cxn (cxn sarcomere)
- m is shortened over both joints and cannot make anymore CB
- to reduce it, you have to shorten at some point
PLS look at notes for examples
What is passive insufficiency?
When an inactive muscle does not have enough length for full motion to occur
- force can be exerted on the bony insertion of m resulting in motion in the direction of the passive pull or checking motion in the opposite direction
- we can only test for passive insufficiency
What is tenodesis (tendon action)
- passive at one joint causes motion at another
- when a motion of a bony segment results from a passive pull
- if a m is significantly shortened, passive insufficiency can be used to produce motion and asset with function
What is an agonist?
prime mover
- for mobility
What is an antagonist?
opposes the prime mover
- passive. cant go further .
- for mobility
What is a co-contraction?
agonist and antagonist contract simultaneously at a joint
- can provide stability
- not active or passive bc firing at same time
- EX: playing tennis/holding racket
Synergist
m that helps the agonist perform the desired motion
EX: pls look at notes there are a lot
What are sensory receptors in the muscles? What are the 2 receptors?
neural components in a muscle fiber that sends sensory afferent to brain so that the brain can send the message back
- Golgi tendon organs
- muscle spindles
Golgi Tendon Organs (GTO)
located in tendon at myotendinous junction
- activated with increased tension
- cause an inhibition of the m when activated
lOOK at notes for EX
Muscle spindles
located around intrafusal m fibers
- sensitive to changes in length and rate of change of length
- when m is on slack (extrafusal fibers), m spindle sends s signal to the cerebellum to tell the intrafusal fibers to shorten
- facilities in m cxn of extrafusal fibers when activated
- sends muscle afferent to brain with efferent response
- spindle looks at how fast you do something
What is the stretch reflex and what is it caused by?
m spindle has quick change in length telling the brain something is happening fast and teh brain tells the opposite to the m to relax so it can elongate
Effects of aging on muscle
- decrease Type II fibers
- you cant see burst moments as well (get up and go test)
- decrease # of MU so remaining MU will have more fibers
- less MU = less recruiting of fibers = less strength - increase in amt of CT
- passive CT, extra CT hardens so it is harder to move which causes fibrosis, you avoid this by passive mvt or e stim
Effects of immobilization on muscle
- decrease # of sarcomeres
- less bc none actively work
- increase sarcomere length as a result of passive shortening
- bc when you try to make a muscle cx,. we dont have optimal length position
- sarcomere length depends on position, so if actin and myosin are pulled apart, they reach for each other bc one side is over lengthened
- increase ratio of CT to m fiber
- loss of wt and atrophy
Osteokinematics
study of mvt of a bone w/out regard for the motion occurring at the joint surface or the forces producing the mvt
Kinematics
study of mvt without regard to forces
kinetics
study of forces producing the motion
Frontal plane: axis of motion and osteokinematic motion?
- A/P axis
- ABD/ADD
Sagittal Plane: axis of motion and osteokinematic motion?
- med/lat axis
- Flex/Ext
Horizontal/Transverse Plane: axis of motion and osteokinematic motion?
- vertical axis
- IR/ER
What does degrees of freedom mean?
- number of independent axes a bone can move around
Example of uniaxial joints?
how many degrees of freedom does it have?
- 1 DF
- elbow, hinge and pivot
- has 3 joints
- flex/ext & pro/sup occurs at humeral/ulnar joint
Example of biaxial joints?
how many degrees of freedom does it have?
- 2 DF
- flex/ext, abd, add,
- convex or concave joint surface in all directions
- condyloid/ovoid or saddle joint
- 1st CMC and sternoclavicular joint
Example of triaxial joints?
how many degrees of freedom does it have?
- 3 DF
- planar joints, ball and socket
- hip and shoulder
what are synarthrodial joints?
bony components connected by CT
- designed for stability
- minimal to no mvt
Fibrous synarthrodial joint examples?
- sutures, inerosseus membrane
- Suture: united by collagenous sutural ligament/membrane
- Gomphosis: peg in a hole, only in teeth
- Syndesmosis: joined by interosseous ligament, fibrous cord or aponeurotic membrane
EX of syndesmosis: tib/fib, radial/ulnar
Cartilaginous synarthrodial joint examples?
bone-cartilage-bone
- allows some mvt
Symphysis: directly joined by fibrocartilage (disc or pad)
covered with hyaline cartilage
EX: pubic symphysis
Sychondrosis: hyaline cartilage forms a body between 2 bones
EX: between ribs and sternum
what are diathrodial joints? Examples?
bones indirectly connected by a joint capsule
- designed for mobility
- facilitates motion and provides stability
EX: discs, plates, menisci
What is a joint capsule? What are the components?
function to enclose joint and enhance stability
- Dense irregular CT
- variable thickness
- poorly vascularized, highly innervated
- capsular ligaments: local thickening of JC
EX: what stops your knee when you hyperextend it?
JC
- a lot of where you get proprioceptive feedback
What makes up the synovial membrane?
sub-intima
intima
what are the components of the subintima and what is its function?
- loose network of tissue
- Attaches to:
1. margins of articular cartilage
2. periosteum (distal to where cartilage ends)
3. JC
what are the components of the intima and what is its function?
- interacts with JC and lines J space
- site for exchange of synovial fluid
- site for hyaluronic acid production
- removes debris from JC
- structural repair of synovium
-Components:
synoviocytes (1-3 layers)
What is the purpose of hyaluronic acid?
keeps friction low
What happens in synovial fluid?
- direct exchange bt synovium intimacy vasculature and synovial fluid
- keeps JS lubricated
- reduces friction
- hyaloronic acid for viscosity
- lubricin
What are the optional components of a JC and their functions?
- disc, plates, menisci, labrum
- increase joint congruence
- absorb compressive forces
- facilitate motion
What us bursa and its functions?
- optional component of JC
- flat, dense irregular CT sac
- lined with a synovial fluid membrane
- filled with a thin fluid
What are Ruffini, where are they located, and what are they sensitive to?
- type 1 sensory supply to JC and synovial membrane
- Sensitive: stretch
- Location: JC on flex side, periosteum, ligaments, tendons
What are Pacini, where are they located, and what are they sensitive to?
- type 2 sensory supply to JC and synovial membrane (SM)
Sensitivity: compression, changes in hydrostatic pressure, and joint movement
Location: throughout JC and fat pads
What are Golgi (GTO), where are they located, and what are they sensitive to?
- type 3 sensory supply to JC & SM
Sensitivity: pressure & extremes of motion
Location: intima of synovium, ligaments, tendons
What are unmyelinated free nerve endings, where are they located, and what are they sensitive to?
- type 4 sensory supply to JC & SM
Sensitivity: noxious.non-noxious mechanical or biomechanical stress
Location: around BV in syonical layer of capsule & fat pads
What is a complex joint? Examples?
has an intra-articular disc bt the joint surfaces
SC joint, TMJ
What are compound joints? Examples?
Has one or more pair of articular surfaces w/in JC
- Elbow: encompasses humero/rad, humero/uln, uln/rad
- Superior tip/fib, fem/fib, fem/tib
Combination of several joints uniting successive segments
kinematic chain
Proximal segment is fixed but distal segment is moving in space is a _____
Open Kinematic Chain
Distal segment is fixed but Proximal segment is moving.. is a _____
Closed Kinematic Chain
EX: standing in knee flexion.
- OKC or CKC
- What is the proximal/fixed segment?
- Distal segment?
- Other joints involved?
- CKC
- prox seg: femur
- distal: tibia
- hip & ankle
Do we mostly function in an OKC or CKC?
CKC
EX: standing plantar flexion
- proximal/fixed segment?
- distal seg?
prox: talus
distal: tibia
EX: seated plantar flexion
- proximal/fixed segment?
- distal seg?
- tibia
2. talus
EX: elbow flex
- proximal/fixed segment?
- distal seg?
- humerus
2. ulna
Arthrokinematics definiton
Study of mvt of one articular surface on another w/out regard to mvt of the bone or the forces producing the mvt
What is an ovoid joint shape and examples?
- JS are curved in the same direction as the articular surface partner
- hinge joints: elbow
- condyloid joints: 2nd MCP
- ball and socket: shoulder
EX: hip.
- femur head in acetabulum
What is a sellar joint shape and examples?
has convex and concave curves on the same articular surface
- saddle shaped: i.e. 1st CMC
- knee, ankle, SC
EX: SC joint.
- looking inferior to superior: sternal protein is convex and clavicle is convex
- looking ant to superior, clavicle is concave and sternal is convex
what mats occur at JS?
- rolling
- gliding (sliding)
- spinning
- normal
Explain a rolling joint motion and give examples
- contact position changes as you move both surfaces. each point on one surface contacts a new point on the other surface
EX: femur rolling across tib
Explain a gliding/sliding joint motion and give examples
same point on one surface contacts new points on the other surface
- joint mobility
- surface that is sliding has the same contact point but changing on the joint that is not moving
- occurs during OKC
EX: fem/tib joint
Explain a spinning joint motion and give examples
contact point doesnt change on one surface just rotates on top of another
- “roll back with slide forward”
EX: radial notch of ulna annular big rad.uln
Explain a normal joint motion and give examples
combo of rolling, spinning, sliding which occur simultaneously
The area covered by convex is ____ than concave
greater
Functionally, roll and glide mvts occur _____
simultaneously
the direction of the gliding in the joint depends on ___
whether the concave or convex surface is moving
the direction of the rolling in a joint is always in the direcion of ___
bone mvt
If a convex surface moves on a stable concave surface, the roll and glide occur in ____ direction
opposite
If a concave surface moves on a convex surface, roll and glide occur in ___ direction
same
pls look at convex concave notes
thx
At the SC joint in retraction, does the roll and glide occur anterior or posterior? what surface is moving?
- concave on convex
- roll and glide both move posteriorly
At the SC joint in protraction, does the roll and glide occur anterior or posterior? what surface is moving
- roll and glide anterior
At the SC joint in elevation and depression, which surface is moving?
convex on concave
joint mobility/glides cannot be performed
voluntarily
joint mobility/glides require ____ and ____ by an examiner
m relaxation, application of passive mvt
We cannot have normal ____ motion if we do not have normal ___ motion
osteokinematic, arthrokinematic
in the treatment plane the line is ____ to to concave surface
parallel
joint glides typically occur ___ in the tx plane
parallel
What directions do joint glides occur in?
- ant/sup
- sup/inf
- med/lat
- distraction
- traction
distraction in joints pulls in the ____ direction to the tx plane
perpendicular
traction in joints pulls in the ____ direction, along the ___ axis of the bone
longitudinal, long axis
does the joint axis remain stationary?
no
what is a closed pack position?
position of the joint that results in
- max tautness of major ligaments
- max surface contact in only 1 position
- taut capsular stretch
- min joint volume due to cap and ligaments being tight
what position allows the maximum stability allowing the least amount of distraction of joint surfaces?
- closed packed position
What is a loose/open packed position
- ligaments and caps are on slack
- max joint volume
- JS distract
- allows spin/roll/glide ot occur
what position do we perform with inflammation and when we assess joint mobility/perform joint mobs?
loose packed
What transports fibroblasts
glycoproteins
