Connective TissueConnective TissueHKIN 473HKIN 473

Group Members:Group Members:

Amy ChuAmy ChuJesse GodwinJesse Godwin

Hale LoofbourrowHale LoofbourrowScott ApperleyScott Apperley

Greg KirkGreg KirkKen AndersonKen Anderson

OverviewOverview

Introduction to Connective TissueIntroduction to Connective Tissue

TendonsTendons

LigamentsLigaments

CartilageCartilage

ConclusionConclusion

IntroductionIntroduction

Connective tissues are situated around the body Connective tissues are situated around the body and play numerous rolesand play numerous roles

Components common to connective tissueComponents common to connective tissue– Collagen FibersCollagen Fibers

Most abundant (parallel in arrangement)Most abundant (parallel in arrangement)Stronger than steelStronger than steel

– Reticular FibersReticular FibersCriss-crossCriss-cross

– Elastic FibersElastic FibersSlightly elasticSlightly elastic

TendonsTendons

Tendons: FunctionTendons: Function

Primary FunctionPrimary Function– Attach muscle to bone thereby transmitting Attach muscle to bone thereby transmitting

tensile loads from muscle to bone to produce tensile loads from muscle to bone to produce movement.movement.

Secondary FunctionSecondary Function– Allows the muscle belly to be at an optimal Allows the muscle belly to be at an optimal

distance from the joint upon which it acts. distance from the joint upon which it acts.

Tendons: AnatomyTendons: Anatomy

86% collagen fibers 86% collagen fibers making them very making them very strongstrong

The connective tissue The connective tissue that runs the length of that runs the length of the muscle joins the muscle joins together into a bundle together into a bundle of connective tissue, of connective tissue, forming the tendonforming the tendon

Tendons: PhysiologyTendons: Physiology

Biomechanical Properties of Biomechanical Properties of TendonsTendons– 4 regions of the graph4 regions of the graph

(1) concave or “toe,” region. (1) concave or “toe,” region. Results form change in the wavy Results form change in the wavy pattern of relaxed collagen fibers pattern of relaxed collagen fibers which become straighter as the which become straighter as the load progresses. Little force is load progresses. Little force is required to elongate tissue required to elongate tissue initially.initially.

(2) linear region. The fibers (2) linear region. The fibers straighten out and stiffness of the straighten out and stiffness of the specimen increases rapidly.specimen increases rapidly.

Tendons: Physiology (con’t)Tendons: Physiology (con’t)

(3) End of linear relation. (3) End of linear relation. When the linear region is When the linear region is surpassed major failure of the surpassed major failure of the fiber bundles occurs. Small fiber bundles occurs. Small force reductions in the curve force reductions in the curve represent early sequential represent early sequential failure of a few greatly failure of a few greatly stretched fiber bundles.stretched fiber bundles.

(4) Maximum load, (4) Maximum load, expressing the ultimate expressing the ultimate tensile strength of the tissue. tensile strength of the tissue. Complete failure of the tissue Complete failure of the tissue to resist load.to resist load.

Tendons: InjuryTendons: Injury

The amount of force that the muscle, The amount of force that the muscle, which the tendon is attached to, can which the tendon is attached to, can generate and the cross sectional generate and the cross sectional area of the tendon are the major area of the tendon are the major factors in predicting injury.factors in predicting injury.

When subjected to loading that When subjected to loading that exceeds the physiological range, exceeds the physiological range, micro-failure takes place even micro-failure takes place even before the yield point is reached.before the yield point is reached.

If muscle contracted, the stress on If muscle contracted, the stress on the tendon can be greatly increased the tendon can be greatly increased with a rapid eccentric contraction.with a rapid eccentric contraction.

Tendons: Viscoelastic BehaviorTendons: Viscoelastic Behavior

Display rate-dependent behavior under loading Display rate-dependent behavior under loading (mechanical properties change with different rates of (mechanical properties change with different rates of loading). loading).

The linear portion of the stress strain curve becomes The linear portion of the stress strain curve becomes steeper with increased loading rates. (ie, there is a steeper with increased loading rates. (ie, there is a higher level of stiffness at higher strain rates)higher level of stiffness at higher strain rates)

With these higher strain rates, tendons can store more With these higher strain rates, tendons can store more energy, require more force to rupture, and undergo energy, require more force to rupture, and undergo

greater elongationgreater elongation..

Tendons: AdaptationsTendons: Adaptations

Factors that affect the mechanical properties of Factors that affect the mechanical properties of tendon include:tendon include:a) a) Maturation and AgingMaturation and Aging

directly related to quality and number of collagen cross linksdirectly related to quality and number of collagen cross links

b) b) PregnancyPregnancytendons and pubic symphysistendons and pubic symphysis

c) c) Mobilization and ImmobilizationMobilization and Immobilization

d) d) NSAID’sNSAID’sshort term administration after injury thought to increase rate of short term administration after injury thought to increase rate of biomechanical restoration of tissue.biomechanical restoration of tissue.

LigamentsLigaments

Ligaments: FunctionLigaments: Function

Tough, white, fibrous, slightly elastic tissuesTough, white, fibrous, slightly elastic tissues

Connect bone to boneConnect bone to bone

Supporting and strengthening jointsSupporting and strengthening joints

Restrict range of motion to prevent excessive Restrict range of motion to prevent excessive movement that could cause dislocation and movement that could cause dislocation and sprainingspraining

Ligaments: AnatomyLigaments: Anatomy

Ligaments and tendons are regular dense Ligaments and tendons are regular dense collagen bundlescollagen bundles– The collagen fibers are closely packed and arranged The collagen fibers are closely packed and arranged

in parallel to give higher tensile strengthin parallel to give higher tensile strength– Ligaments are strongest with forces parallel to the Ligaments are strongest with forces parallel to the

fiber arrangement (along axis of the fibers)fiber arrangement (along axis of the fibers)

Highly avascularHighly avascular– Heal slowlyHeal slowly

Very similar to tendonsVery similar to tendons

Ligaments: ExamplesLigaments: Examples

Ligaments: SprainsLigaments: Sprains

Can be caused by the severe stretching or tearing or a Can be caused by the severe stretching or tearing or a ligamentligament

Often caused by twisting or wrenching movementOften caused by twisting or wrenching movement

Symptoms: pain, swelling, and sometimes bruisingSymptoms: pain, swelling, and sometimes bruising

Treatment: immediate cold compress and elevation, long Treatment: immediate cold compress and elevation, long term bandaging and/or splintingterm bandaging and/or splinting– In rare cases, surgery my be a useful alternativeIn rare cases, surgery my be a useful alternative

Full recovery may take up to 5 weeksFull recovery may take up to 5 weeks

CartilageCartilage

Cartilage: AnatomyCartilage: Anatomy

• Dense network of collagen and elastin fibersDense network of collagen and elastin fibers

• Fibers are embedded in a ground substance of Fibers are embedded in a ground substance of chrondroitin sulfatechrondroitin sulfate

• Collagen provides strengthCollagen provides strength

• Elastin provides elasticityElastin provides elasticity

• Cartilage is an avascular tissueCartilage is an avascular tissue

Cartilage: TypesCartilage: Types

Three primary types based on proportion Three primary types based on proportion of chondrocytes, elastin fibers and of chondrocytes, elastin fibers and collagen fiberscollagen fibers

1. Fibrocartilage1. Fibrocartilage

2. Elastic Cartilage2. Elastic Cartilage

3. Hyaline Cartilage3. Hyaline Cartilage

1. Firbrocartilage1. Firbrocartilage

Large proportion of Large proportion of collagen fiberscollagen fibers

Provides strength and Provides strength and supportsupport

Found in the pubic Found in the pubic symphysis, symphysis, intervertebral discs, intervertebral discs, menisci of the kneemenisci of the knee

Source: Polychondritis Educational Society, Ltd

2. Elastic Cartilage2. Elastic Cartilage

Chondrocytes reside in a Chondrocytes reside in a “threadlike network” “threadlike network” provided by elastic fibersprovided by elastic fibers

Provides strength and Provides strength and elasticity while elasticity while maintaining shapemaintaining shape

Found in the epiglottis Found in the epiglottis and external earand external ear Source: Polychondritis Educational Society, Ltd

3. Hyaline Cartilage3. Hyaline Cartilage

Most abundant cartilage Most abundant cartilage composed of fine composed of fine collagen fibres with many collagen fibres with many chondrocyteschondrocytes

Provides flexibility and Provides flexibility and supportsupport

Found in the nose, larynx, Found in the nose, larynx, bronchi, trachea and on bronchi, trachea and on the anterior ends of ribsthe anterior ends of ribs

Source: Polychondritis Educational Society, Ltd

Cartilage: Endochondral OssificationCartilage: Endochondral Ossification A further function of Hyaline Cartilage is in the formation of A further function of Hyaline Cartilage is in the formation of

long boneslong bones

Starting in the fetus, cartilage calcifies until full bone growth Starting in the fetus, cartilage calcifies until full bone growth has been achieved, typically at the age of 25has been achieved, typically at the age of 25

Tortora & Grabowski, 2000

Articular CartilageArticular Cartilage

Hyaline or Hyaline or Fibrocartilage found Fibrocartilage found in joints on the in joints on the articulating surfaces articulating surfaces of bonesof bones

Provides a smooth, Provides a smooth, slippery surface that slippery surface that reduces friction and reduces friction and absorbs shock in absorbs shock in jointsjoints

Tortora & Grabowski, 2000

Cartilage: OsteoarthritisCartilage: Osteoarthritis Painful condition in which Painful condition in which

the articular cartilage the articular cartilage between bones between bones degeneratesdegenerates

11% of people older than 11% of people older than 64 years old experience 64 years old experience symptoms of osteoarthritissymptoms of osteoarthritis

Glucosamine and Glucosamine and chondroitin sulfate have chondroitin sulfate have been found to relieve some been found to relieve some pain symptomspain symptoms

Cartilage: Knee MenisciCartilage: Knee Menisci

The medial and lateral The medial and lateral menisci are wedge-like menisci are wedge-like cushions of fibrocartilage cushions of fibrocartilage found in the knee joint found in the knee joint between the tibia and between the tibia and femurfemur

Knee menisci provide Knee menisci provide stability, support in stability, support in carrying weight and allow carrying weight and allow movement in many movement in many directionsdirections

American Academy of Orthopaedic Surgeons, 2001

Cartilage: Meniscal TearsCartilage: Meniscal Tears Damage to the menisci can Damage to the menisci can

occur in decelerating, twisting, occur in decelerating, twisting, cutting or pivotingcutting or pivoting

Meniscal tears may cause loss Meniscal tears may cause loss of range of motion, pain, of range of motion, pain, stiffness and knee lockingstiffness and knee locking

Meniscal injuries are hard to Meniscal injuries are hard to heal because of the absence of heal because of the absence of blood supplyblood supply

Meniscal injuries may require Meniscal injuries may require surgical treatmentsurgical treatment

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