Transcript Connective Tissue

Connective Tissue
HKIN 473
Group Members:
Amy Chu
Jesse Godwin
Hale Loofbourrow
Scott Apperley
Greg Kirk
Ken Anderson
Overview
Introduction to Connective Tissue
Tendons
Ligaments
Cartilage
Conclusion
Introduction
Connective tissues are situated around the body
and play numerous roles
Components common to connective tissue
– Collagen Fibers
Most abundant (parallel in arrangement)
Stronger than steel
– Reticular Fibers
Criss-cross
– Elastic Fibers
Slightly elastic
Tendons
Tendons: Function
Primary Function
– Attach muscle to bone thereby transmitting
tensile loads from muscle to bone to produce
movement.
Secondary Function
– Allows the muscle belly to be at an optimal
distance from the joint upon which it acts.
Tendons: Anatomy
86% collagen fibers
making them very
strong
The connective tissue
that runs the length of
the muscle joins
together into a bundle
of connective tissue,
forming the tendon
Tendons: Physiology
Biomechanical Properties of
Tendons
– 4 regions of the graph
(1) concave or “toe,” region.
Results form change in the wavy
pattern of relaxed collagen fibers
which become straighter as the
load progresses. Little force is
required to elongate tissue
initially.
(2) linear region. The fibers
straighten out and stiffness of the
specimen increases rapidly.
Tendons: Physiology (con’t)
(3) End of linear relation.
When the linear region is
surpassed major failure of the
fiber bundles occurs. Small
force reductions in the curve
represent early sequential
failure of a few greatly
stretched fiber bundles.
(4) Maximum load,
expressing the ultimate
tensile strength of the tissue.
Complete failure of the tissue
to resist load.
Tendons: Injury
The amount of force that the
muscle, which the tendon is
attached to, can generate and the
cross sectional area of the tendon
are the major factors in predicting
injury.
When subjected to loading that
exceeds the physiological range,
micro-failure takes place even
before the yield point is reached.
If muscle contracted, the stress on
the tendon can be greatly increased
with a rapid eccentric contraction.
Tendons: Viscoelastic Behavior
Display rate-dependent behavior under loading
(mechanical properties change with different rates of
loading).
The linear portion of the stress strain curve becomes
steeper with increased loading rates. (ie, there is a
higher level of stiffness at higher strain rates)
With these higher strain rates, tendons can store more
energy, require more force to rupture, and undergo
greater elongation.
Tendons: Adaptations
Factors that affect the mechanical properties of
tendon include:
a) Maturation and Aging
directly related to quality and number of collagen cross links
b) Pregnancy
tendons and pubic symphysis
c) Mobilization and Immobilization
d) NSAID’s
short term administration after injury thought to increase rate of
biomechanical restoration of tissue.
Ligaments
Ligaments: Function
Tough, white, fibrous, slightly elastic tissues
Connect bone to bone
Supporting and strengthening joints
Restrict range of motion to prevent excessive
movement that could cause dislocation and
spraining
Ligaments: Anatomy
Ligaments and tendons are regular dense
collagen bundles
– The collagen fibers are closely packed and arranged
in parallel to give higher tensile strength
– Ligaments are strongest with forces parallel to the
fiber arrangement (along axis of the fibers)
Highly avascular
– Heal slowly
Very similar to tendons
Ligaments: Examples
Ligaments: Sprains
Can be caused by the severe stretching or tearing or a
ligament
Often caused by twisting or wrenching movement
Symptoms: pain, swelling, and sometimes bruising
Treatment: immediate cold compress and elevation, long
term bandaging and/or splinting
– In rare cases, surgery my be a useful alternative
Full recovery may take up to 5 weeks
Cartilage
Cartilage: Anatomy
• Dense network of collagen and elastin fibers
• Fibers are embedded in a ground substance of
chrondroitin sulfate
• Collagen provides strength
• Elastin provides elasticity
• Cartilage is an avascular tissue
Cartilage: Types
 Three primary types based on proportion
of chondrocytes, elastin fibers and
collagen fibers
1. Fibrocartilage
2. Elastic Cartilage
3. Hyaline Cartilage
1. Firbrocartilage
 Large proportion of
collagen fibers
 Provides strength and
support
 Found in the pubic
symphysis,
intervertebral discs,
menisci of the knee
Source: Polychondritis Educational Society, Ltd
2. Elastic Cartilage
 Chondrocytes reside in a
“threadlike network”
provided by elastic fibers
 Provides strength and
elasticity while
maintaining shape
 Found in the epiglottis
and external ear
Source: Polychondritis Educational Society, Ltd
3. Hyaline Cartilage
 Most abundant cartilage
composed of fine
collagen fibres with many
chondrocytes
 Provides flexibility and
support
 Found in the nose, larynx,
bronchi, trachea and on
the anterior ends of ribs
Source: Polychondritis Educational Society, Ltd
Cartilage: Endochondral Ossification
 A further function of Hyaline Cartilage is in the formation of
long bones
 Starting in the fetus, cartilage calcifies until full bone growth
has been achieved, typically at the age of 25
Tortora & Grabowski, 2000
Articular Cartilage
 Hyaline or
Fibrocartilage found
in joints on the
articulating surfaces
of bones
 Provides a smooth,
slippery surface that
reduces friction and
absorbs shock in
joints
Tortora & Grabowski, 2000
Cartilage: Osteoarthritis
 Painful condition in which
the articular cartilage
between bones
degenerates
 11% of people older than
64 years old experience
symptoms of osteoarthritis
 Glucosamine and
chondroitin sulfate have
been found to relieve some
pain symptoms
Cartilage: Knee Menisci
 The medial and lateral
menisci are wedge-like
cushions of fibrocartilage
found in the knee joint
between the tibia and
femur
 Knee menisci provide
stability, support in
carrying weight and allow
movement in many
directions
American Academy of Orthopaedic Surgeons, 2001
Cartilage: Meniscal Tears

Damage to the menisci can
occur in decelerating, twisting,
cutting or pivoting

Meniscal tears may cause loss
of range of motion, pain,
stiffness and knee locking

Meniscal injuries are hard to
heal because of the absence of
blood supply

Meniscal injuries may require
surgical treatment
Thank You