9/11 Dennis_PPT_Cartilage Flashcards
Overview of Cartilage
- Semi-rigid tissue comprised of cells & extracellular matrix
- ECM containing ____& _____ fibers
- Crucial to the survival of _____
- Flexible & resilient support
- No nerve supply or lymphatics
- Avascular
collagen and elastic
chondrocytes
Cartilage Components
what are the two component cells?
- Chondroblasts (immature): cells that secrete cartilage matrix - Mitotic capabilities
- Chondrocytes: mature cartilage cells in lacunae - Surrounded by & maintain matrix
cartilage components
what three elements in the matrix?
- Compartmentalized: territorial vs. interterritorial matrix
- Fibers: • Type II collagen is predominant • Type I collagen is present in fibrocartilage & outer perichondrium • Elastin fibers in elastic cartilage
- Ground substance, composed of proteoglycans: • Hyaluronic acid • Chondroitin sulfate • Keratin sulfate • Aggrecan
Three types of cartilages?
- Hyaline: • Surrounded by perichondrium • Contains type II collagen • Location: articular cartilage, larynx, trachea, ribs, embryonic development
- Elastic (hyalin + elastic fibers): • Surrounded by perichondrium • Contains type II collagen • Location: external ear, epiglottis, auditory tube
- Fibrocartilage: • Lacks a perichondrium • Contains type I collagen (high impact) • Location: intervertebral discs, pubic symphysis, TMJ
hyalin cartilage
- Chondrocytes can be found in _____ groups
- Gel-like substance
- Amorphous, but homogeneous
- Surrounded by perichondrium • **Articular cartilages lack perichondrium**
isogenous
cartilage matrix
- ______matrix: moderately staining, consists of type II collagen randomly arranged • High GAGs • Decreased collagen
- ____matrix: surrounds the territorial matrix • Less intensely staining • More collagen II, fewer proteoglycans
Territorial
Interterritorial
An isogenous group (lat. “equal origin”) is a cluster of chondrocytes, all formed through division of a single progenitor cell, found in hyaline cartilage, elastic cartilage, and fibrocartilage, growing by interstitial growth.
The Growing Skeleton
Perichondrium
- Dense _____ CT
- Contains ____ supply
- ____& ____ cartilage only
- Source of ______ cells
irregular
vascular
Hyaline & elastic
new cartilage
There are two layers of perichondrium?
- Fibrous layer: outer layer that produces type I collagen & elastin • Transitional zone between cartilage & surrounding general CT
There are vascular running through the layer
- Chondrogenic layer: inner layer that differentiates into chondroblasts • Secretes type II collagen
Elastic Cartilage
- Components of ____cartilage PLUS ____ fibers within the matrix • Orcein or resorcinfuchsin stains
- Elastic fibers allow for recoil/rebound
- Retains shape after deformation
- Surrounded by ______
hyaline and elastic
perichondrium
Fibrocartilage
- Combination of ____ cartilage & _____ CT • Type I & type II collagen • Less cartilage matrix • Lacks a perichondrium
- Chondrocytes are aligned in rows & isogenous groups
- Fibers oriented in the direction of functional stress
- Withstands compression & shearing forces
hyaline and dense regular
Chrondrogenesis, two types of growths?
Appositional Growth and Interstitial Growth
Appositional Growth
where does it grow on?
- Forms new cartilage on surface of existing cartilage
- Chondrogenic cells located within inner layer of perichondrium • Produce type I collagen
- After growth initiated, cells → chondroblasts → secrete type II collagen II & ground substance
Interstitial Growth
where does it happen?
- Takes place within a cartilage mass
- Chondrocytes divide within lacunae, creating new isogenous groups • Secrete more matrix • Divides daughter cells • Increases mass of cartilage
- Limited by avascular nature
Cartilage Repair
- Limited repair capacity, due to ____ nature
- Repair cartilage forms when perichondrium is involved • Matrix composition intermediate of hyaline & fibrous cartilage • Contains types I & II collagen • Can stimulate bone growth
- Facilitates the healing of a bone fracture
- Repair is _____
avascular
age-dependent
Joints
- An articulation, or joint, is the place where a bone meets another bone, cartilage, or teeth
- Anatomical vs. physiological classification
- Stability compromises _____
mobility
Synovial Joints
articular capsule, what is the CT type for the outer fibrous layer?
dense regular CT
synovial joint
Synoviocytes
Two types of synovial cells?
- Type A Macrophage-like synovial cells • Phagocytic • Contain lysosomes to clear articular cavity of debris formed by friction of articular cartilages • 25% of cells lining the synovium • Regulate inflammatory events
- Type B Fibroblast-like synovial cells • Produce synovial fluid (plasma filtrate) • Produce hyaluronate that combines with synovial fluid (via H2O) • Lubricates/nourishes the articular cartilage
Articular Cartilage
- Collagen fibers run ______ to the tissue surface & bend gradually to form an arc
- Distinct layering
- Superficial (tangential) zone • Intermediate (transitional) zone • Deep (radial) zone • Calcified zone
perpendicular
what are the four layers in the articular cartilage?
superficial
intermediate
deep
calcified
Osteoarthritis
- Degenerative joint disease
- Pathogenesis of osteoarthritis is unknown, but is related to ____& injury of ____
- Characterized by: • Chronic joint pain • Various degrees of joint deformity & destruction of the articular cartilage
- Commonly affects weight-bearing joints: hips, knees, lower lumbar vertebra, joints of the hand & foot
- Early stages: ____ layer of the articular cartilage is disrupted
- Late stages: destruction of the cartilage extends to the bone, where the exposed ____ bone becomes a new articular surface
- Progressive reduction of mobility & increased pain
aging and articular cartilage
superficial
subchondral
summary
