Cartilage Flashcards
3 functions of cartilage
Support
Cushion
Template for mature bone
Mature cartilage is (3)
Avascular
Aneural
Alymphatic
How does cartilage receive nourishment if its avascular?
Blood vessels of surrounding CT (pericondrium= hyaline and elastic cartilage)
Synovial fluid within joint capsule (without pericondrium=fibrocartilage)
What is the relationship between cartilage thickness and nutrients/oxygen?
Nutrients and oxygen must diffuse through the water of hydration within ECM which limits thickness of cartilage.
Acellular components of cartilage
ECM
- ->Water
- ->Ground substance
- ->Fibers
Components of ground substance and fibers in ECM
Ground substance
- aggrecans
- hyaluronic acid
- GAG
- Proteoglycans
Fibers
- Collagen
- Elastic
Cellular components of cartilage (3)
Chondrogenic cells
Chondroblasts
Chondrocytes
Immature cells that secrete ECM in cartilage
chondroblasts
Mature cells that are enveloped by the ECM into lacunae
Chondrocytes
Types of growth in cartilage (2)
Appositional growth
Interstitial growth
Perichondrium consists of 2 layers
- Outer fibrous layer
- Inner cellular layer
Outer fibrous layer of perichondrium made of
Type I collagen
Fibroblasts
Blood vessels
Inner cellular layer of perichondrium made of
chondrogenic cells
Chondrogenic cells differentiate into (which do what)?
Chondroblasts which make ECM and become chondrocytes
T/F Interstitial growth contains perichondrium
F
In interstitial growth, as cells make ECM
They move away from one another
Where does interstitial growth occur
Articular cartilage (lacks perichondrium) and epiphyseal plates
T/F Interstitial growth has chondrenic cell layer
F
What are isogenous groups
In cartilage
Pairings of chondrocytes in lacunae
Territorial matrix
Immediately surrounding chondrocyte (more basophilic than interterritorial matrix)
Territorial matrix is poor in? Rich in?
Poor-collagen
rich-proteoglycans (chondroitin sulfate)
Interterritorial matrix
Area outside of territorial matrix (less basophilic that territorial matrix)
Interterritorial matrix rich in? poor in?
Rich-type II collagen
Poor-Proteoglycans (chondroitin sulfate)
3 types of cartilage
Hyaline cartilage
Elastic cartilage
Fibrocartilage
Places hylaine cartilage is
Nose
Tracheal rings
larynx
cartilage part of ribs
bronchi
articular surfaces
Color of hyaline cartilage
Blue/gray and translucent
Major component of hyaline cartilage
Type II collagen
Hyaline cartilage is important in
Endochondral ossification of long bones
Special form of hyaline cartilage
Articular cartilage (joint surfaces) Not covered by perichondrium
Elastic cartilage phenotype
Yellow and opaque
Where is yellow cartilage found
ear pinnae
external and internal auditory tubes
parts of larynx
High concentration of what in elastic cartilage
Elastic cartilage with type II collagen
What has more chondrocytes, elastic cartilage or hyaline cartilage
Elastic cartilage
Where is fibrocartilage found
Connections of tendons to bone
Intervertebral discs
Pubic symphsis
Menisci of femorotibiial joint
Meniscus of TMJ
T/F Fibrocartilage includes perichondrium
F
What’s found in fibrocartilage
Large bundles of Type I collagen
Fibrocartilage resists
Compression and shear forces
Patters seen in fibrocartilage
Herringbone pattern
Chondrocytes in rows of isogenic groups
Cartilage repair (with perichondrium) in young
Perichondrium still active and ensures supply of mesenchymal cells
Interstitial and appositional growth activity present
Cartilage repair (with perichondrum in adult)
Perichondrium not active=regenerative activity decreased\
Loss of interstitial and appositional growth
Repair by laying down granulation tissue which can turn into fibrocartilage (scar tissue)
Cartilage repair (without perichondrium)-Fibrocartilage
repairs poorly
Cartilage repair (without perichondrium)-Articular cartilage
Superificial-compensatory secretion by chondrocytes (pseudointerstial growth)
Full thickness-when damage to subchondral bone…stem cells differentiate into fibrous CT, fibrocartilage, or bone
Chondrogenic cell physical traits
- shape
- nucleus
- organelles
- mito
- ribosomes
Spindle shaped
Ovoid nucleus
Small Golgi appartus
Few mitochondria
Lots of free ribosomes
Chondrogenic cells differentiate into (2)
Chondroblasts or osteoprogenitor cells
Chondroblasts are derived from (2)
Mesenchymal cells within center of chondrification
OR
Chondrogenic cells of inner layer of perichondrium
Chondroblast physical traits
- Organelles
- Mito
Lots of RER
Well developed Golgi apparatus
Lots of mito
Lots of secretory vessels
T/F chondroblasts help with interstitial growth
T
Chondrocyte physical appearance
Young
-Oraganelles
-Mito
Old
- Organelles
- Ribosomes
Young
lots RER
well developed Golgi apparatus
lots of mito
Old
Lower amounts of organelles
Lots of free ribosomes
Chondrocytes and lacunae
-Dehydration
Chondrocytes are in lacunaes
If cell becomes dehydrated, cell pulls away from lacunae
White space, is lacunae (“shell”:
Lavender haze surrounding chondrocyte nucles
cytoplasm
Purpose of articular cartilage
Cushion
