Connective Tissue and Articular Cartilage Flashcards
Type II collagen is found in
Hyaline cartilage. thinner than type I, lower tensile strength, provide framework, structure for other tissues
Where is elastin found?
hyaline cartilage, ligamentum flavum
GAGs are found in Ground Substance, have a ____charge and are Hydro_____
negative, philic
What does the water provide in ground substance
diffusion of nutrients, provides mechanical properties
Where are fibroblasts found?
ligaments, tendons, Supportive CTs
Where are Chondrocytes found?
hyaline articular cartilage, fibrocartilage
composition of dense connective tissue
HIGH type I collagen, LOW elastin and fibroblasts
ligaments, tendons, and capsules are examples of
dense connective tissue
These characteristics describe which type of tissue
poor healing (low vascularity), adapts to stress/strain with increased stiffness (increased collagen and GAG synthesis)
Where is irregular dense connective tissue found?
joint capsule
Which type of Dense connective tissue is resistant to tensile forces in MULTIPLE directions?
Irregular (joint capsule)
how is collagen arranged in irregular dense connective tissue?
irregular in ground substance
Which type of connective tissue is orderly and has a parallel arrangement of collagen?
Regular Dense Connective Tissue
Which has more elastin? Ligament or Tendons
Tendons - transmit large forces from muscle to bone
Regular dense connective tissue in ligaments and tendons resist tension along the _____ axis
longitudinal
How long is the Inflammatory Phase of healing?
1-10 days
How long is the Proliferation (consolidation) phase?
3-30 days
How long is maturation (remodeling) phase
3-360 days
Which phase of healing are neutrophils and macrophages active?
Inflammatory phase
What is the body’s natural response to injury
inflammatory phase
Connective Tissue is rebuilt with _____ tissue in the proliferation phase
granulation
Fibroblasts are active in which phase of healing
proliferation
In Maturation phase, collagen remodels from Type ___ to Type ___
III to I
On a load-deformation curve, describe the plastic region
top of plateau to the ultimate failure point
In Load-Deformation curve, what is the elastic region
the slope
The yield point in the load deformation curve is where which two sections meet?
elastic and plastic
In a stress strain curve, what is the area under the curve
energy
the slope of elastic region in a stress strain curve is
stiffness
Since biological materials are viscoelastic, there is a toe region. describe it
non linear region. before the elastic region
When does viscoelastic creep occur
when exposed to a constant load
What type of stretches are thought to bring on plastic changes to connective tissue
slow, low-intensity, and long-duration stretches
What does the slope look like in the stress strain curve when we add a faster loading rate
steeper slope and increase stiffness
Stress-relaxation is a stress response that occurs when exposed to a constant ______
deformation
describe what is occurring when there is a high rapid high initial stress followd by a slow decreasing stress required to maintain the deformation
stress-relaxtion
Name the type of collagen: thick, little elongation, stiff, strong, binds, supports bony articulation
found in: ligaments, fibrous Joint capsules, tendons
Type 1
The organic matrix of articular cartilage makes up 15-30% of the volume. What provides the structural framework?
Collagen (Type II) within proteoglycan solution
List one function of articular cartilage
- increase area of load distribution for joints
- attenuate joint contact stresses
- provide a smooth, wear resistant bearing surface
What makes up the majority of the composition of articular cartilage?
water, salts, glycoproteins, lipids - 60-85% of volume
Organic matrix - 15-30%
chondrocytes - 10%
Why is there a near frictionless behavior between joint surfaces?
synovial fluid
Mechanical properties of Articular cartilage
high tensile stiffness and strength
cannot resist compression well
anisotropic - collagen fiber arrangement and densities vary
bi-phasic material - fluid and solid
Where is water concentrated in the articular cartilage?
near articular surface
What does water permit in articular cartilage
exchange of gases nutrients and waste products between chondrocytes and synovial fluid
What supports more than 90% of the applied load on a joint?
pressurization
The magnitude of stress required to maintain the equilibrium displacement decreases over time. what definition is this?
stress-relaxation.
What is shear stiffness of articular cartilage from.
collagen only, not interstitial fluid flow in pure shear
What is the splitting of the cartilage surface called?
Fibrillation
What happens to water content and permeability in the degeneration of articular cartilage?
they both increase
Changes in collagen and PG content and structure
Loosening of structure (increased permeability and fluid content)
increased fluid flow and decreased ability to resist loading are all indicators of what?
osteoarthritis
What are the three proposed mechanisms for the wearing out of cartilage?
1 - tensile failure of collagen fiber network- accumulated tissue damage leads to lower strength
2 - ‘washout’ of PGs from extracellular matrix from repeated fluid exudation resulting in decreased stiffness and increased permeability
3 - rapid application of high loads - no time for stress- relaxation ( fluid redistribution) resulting in high stresses that may cause damage
An anatomical example of a 2nd class lever and explain why it’s 2nd class.
The foot is an example of a 2nd class lever when in plantar flexion because the load (BW) is between internal force (calf muscles) and the fulcrum(ball of the foot)
