Cartilage Flashcards
Hyaline cartilage- Cells:
Chondroblasts & chondrocytes
Hyaline cartilage-• Extracellular matrix:
Type II collagen fibers
GAGs- hyaluronic acid and glycoproteins
Hyaline cartilage-Growth:
Appositional & interstitial growth
Hyaline cartilage-Degeneration:
Does not readily degenerate
Hyaline cartilage-Calcification
Calcifies – bone formation & aging
Hyaline cartilage-Functions:
Supportive • Cushioning • Shock absorber • Growth plate • Model for bone formation
Hyaline cartilage-Histology
•Matrix has a “glassy” appearance because fibers and ground substance has the same refractive index •ECM correlates to function! • Collagen • Sulfated groups
Hyaline cartilage-Locations in the body
- Nose (cartilaginous portion)
- Tracheal and bronchial rings
- Laryngeal cartilages
- Costal cartilages
- Articular surfaces of long bones
- Epiphyseal growth plate
- Fetal skeleton
Appositional Growth
occurs from chondrogenic cells in the perichondrium differentiating into chondroblasts, forming a new layer of cartilage around the periphery of the existing cartilage
Appositional Growth
occurs from chondrogenic cells in the perichondrium differentiating into chondroblasts, forming a new layer of cartilage around the periphery of the existing cartilage
Interstitial Growth
occurs only in young cartilage
from cell divisions within the
cartilage
Regeneration-Hyaline cartilage
regenerates very
poorly and often the
perichondrium forms
scar tissue
Articular cartilage
type of Hyaline cartilage found at
articular surfaces
• does not have perichondrium
Various regions of articular cartilage:
- Tangential layer
- Transitional layer
- Radial layer
- Calcified cartilage
Elastic cartilage-Cells:
• Chondroblasts and chondrocytes
Elastic cartilage-Extracellular matrix:
Type II collagen fibers & elastic fibers
• GAGs and glycoproteins, multi-adhessive
glycoproteins
Elastic cartilage-Growth:
Appositional & interstitial growth
Elastic cartilage-Degeneration:
Does not readily degenerate
Elastic cartilage-Calcification:
Never calcifies
Elastic cartilage-Function:
Support with flexibility
Elastic cartilage-Locations in the body:
- Pinna of the ear
- External acoustic meatus
- Eustachian tube
- Epiglottis
Elastic cartilage v hyaline cartilage
•Perichondrium present •Does not degenerate as readily as hyaline cartilage •Is often found with hyaline cartilage
Fibrocartilage-Cells:
• Fibroblasts transform to chondrocytes
under stress
Fibrocartilage-ECM:
• produced by chondrocytes and fibroblasts • Predominantly Type I collagen fibers • Also contains Type II collagen fibers • GAGs - predominantly chondroitin and dermatan sulphates
Fibrocartilage-Growth:
• Only interstitial growth (due to
absence of perichondrium)
Fibrocartilage-Function
Resists deformation under stress
Support and tensile strength
Fibrocartilage-Locations in the body
- Intervertebral disc (annulus fibrosis)
- At the pubic symphysis
- Medial & lateral menisci
- Attachment of ligament to bone
- Intersections of some tendons and ligaments
- Articular disc
Fibrocartilage- general
-Absence of perichondrium • Matrix contains type I (mainly) & type II collagen fibers -These fibers can be seen here with H&E and trichrome staining.
Osteoarthritis
It is a degenerative joint disease that predominantly affects the weight bearing
joints
- Histopathological findings:
Early- articular cartilage loses its smooth appearance (surface fibrillations, flaking)
Later- progressive erosion until exposure of underlying bone (eburnation, osteophyte
formation, cystic degeneration)
