Cartilage Lecture Flashcards
What is a functional unit?
The matrix
What are bone and cartilage considered?
CT
C and B serve as Ion reservoir
Calcium (99%),
Phosphorus (85%)
Bones are derived from…
Mesenchyme (embryonic CT)
Face bones are derived from…
Ectomesenchyme (neural crest deriv)
What is the major mineral that forms bone?
Hydroxyapatite
What type of series does cartilage enamel form of biomineralized tissues
continuous series
What controls the degree of mineralization of tissues?
SCPP genes
What is a major fiber in cartilage?
Collagen
What are the 3 components of cartilage?
- Cells (chondrocytes)
- Fibers (collagen)
- Ground substances (proteoglycans)
Is connective tissue avascular and anervous?
-Yes (no pain!)
-Surrounded bydense connective tissue called perichondrium
Physical characteristics of cartilage
Semirigid
pliable
gelatinous
not compressible
smooth
ID: Perichondrium, Chondroblast, Chondrocyte
Where do chondrocytes live?
In lecuna
ID: matrix, chondrocyte, lecuna
Hyaline cartilage images
Hyaline cartilage functions
- most dominant type of cartilage
- provides still but flexible support; can break
- reduces friction in bony areas
Hyaline cartilage locations
- ribs
- joints
- larynx, trachea, bronchi
- nasal septum
What type of collagen in hyaline cartilage
Type 2
Elastic cartilage images
Elastic cartilage functions
- provides support, but tolerates distortion without damage and returns to original shape; does not break
Elastic cartilage locations
- external ear
- epiglottis
- auditory tube
Elastic cartilage type of collagen
Type 2
Fibrous cartilage images
herringbone
Fibrous cartilage functions
- resists compression to twist and force
- prevents bone-to-bone contact
- limits relative movements
Fibrous cartilage locations
- knee/meniscus
- pubic bones/pelvis
- intervertebral discs
Fibrous cartilage type of collagen
Types 1+2
Which collagen type anchors cells to matrix?
Collagen VI
Which GAGS are specifically associated with cartilage?
- hyaluronan
- chondroitin sulfate
- keratin sulfate
What is an aggrecan aggregate?
Aggrecan is a large proteoglycan with chondroitin sulfate and keratan sulfate chains that endow articular cartilage with its ability to withstand compressive loads
Aggrecan aggregate charge
negatively charged
What are the 2 most important multi-adhesive proteins for cartilage problems?
- anchorin
- fibronectin
What is the function of multiadhesive proteins?
- Influence interactions of chondrocyte and molecules in the ECM
- Can be used as clinical markers of cartilage degeneration in articular cartilage of joints
Do chondrocytes fill the lacunae?
- Young ones do, old ones do not
Chondrocyte image with young and old chondrocytes
*White ring = old
Chondrocytes–Isogenous Groups
- Isogenous groups are a group (up to 8) chondrocytes with a single origin
Capsular matrix
- darker
- type 6 collagen
- directly in contact w chondrocytes
Territorial matrix
- lighter
- secreted by isogenous group
- area around cell
Matrix components ID
What type of collagen in perichondrium?
T1
Define perichondrium
- regular, white, fibrous CT that surrounds cartilage
What type of cartilage has perichondrium?
HYALINE ONLY
2 portions of perichondrium
- fibrous (outside)
- cellular (inside)
Perichondrium ID
What type of capsule do joints have?
synovial capsule with fluid (2 layers of cartilage working against each other)
T/F: articular cartilage is a type of hyaline cartilage?
TRUE
What is a tide mark the boundary for?
Boundary between calcified and uncalcified cartilage
articular cartilage layers
- tangential
- transitional
- radial
- calcified (transitional tissue, attached cartilage to bone)
- bone
articular cartilage layers ID
Type 2 collagen orientation
- parallel to surface
- perpendicular to bone
Why is osteoarthritis painful?
bone to bone contact (bone is innervated)
Normal vs OA Cartilage
How many ways to grow cartilage?
2; interstitial and appositional
Interstitial growth
- Slow
- Resisted by matrix
- Ex: isogenous group division (made by mitosis)
Apositional growth
- Faster
- Not limited by matrix
- Comes from perichondrium
- Involves the addition of new cells to the surface of the tissue
chondroblast vs chondrocyte
blast: a cell that secretes the matrix of bone, but is not fully enclosed in matrix
cyte: cell inside of tissue, embedded in matrix
*chondroblasts eventually form chondrocytes via chondrogenesis
T/F: there is perichondrium in joints?
FALSE
Apositional growth diagram
ID type of cartilage
Hyaline
ID
Elastic
ID
Elastic
ID
Elastic
ID
Elastic
ID
Elastic
T/F: there is perichondrium in fibrocartilage?
FALSE
ID
Fibrocartilage
ID
Fibrocartilage
Chondrogenesis steps
- condensation
- proliferation and differentiation
- differentiation and maturation
- terminal differentiation
ID
Fibrocartilage
Chondrogenesis phases
- MSCs
- Chondroprogenitors
- Chondroblasts
- Chondrocytes
- Hypertrophic chondrocytes
Appositional growth image
Interstitial growth image
Repair of cartilage
- limited due to avascularity of matrix (must be through diffusion)
- repair is easier if perichondrium is involved and present
- damaged cartilage is usually replaced by dense connective tissue
- if blood vessels enter the wound, bone grows instead of cartilage (pain follows)
- Hyaline cartilage calcifies due to age and is replaced by bone
