Cartilage and Bone Flashcards
3 types of cartilage
hyaline
elastic
fibrocartilage
Why doesnt cartilage heal well?
Bc it is avascular and have immoble chondrocytes with limited proliferation
Components of the Hyaline cartilage matrix
Homogenous amorphous matrix of:
- type II collagen
- GAGs
- proteoglycans
- glycoproteins
Characteristics of Hyaline Cartilage
Chondrocytes located in lacunae
Hyaline cartilage has perichondrium except at articular surfaces
Low friction
Highly hydrated
calcifies with aging
Componets of elastic cartilage matrix
Hyaline Matrix:
- proteoglycan
- glycoproteins
- type II collagen
- GAGs
PLUS elastic fibers and materials
Charcteristics of elastic cartilage
elastic properties
doesnt calcify with aging
Components of fibrocartilage
Hyaline cartilage PLUS dense regular connective tissue
Chondrocytes, some fibroblasts
Collagen fibers (type I and type II)
No perichondrium
Characteristics of fibrocartilage
Resistance to compression and shearing (‘shock absorber’)
Intervertebral discs, symphysis pubis, menisci of knee joint
Calcification of fibrocartilaginous callus during bone repair)
Steps of chondrogenesis
mesenchyme generates chondroblasts
chondroblasts secrete matrix, become isolated chondrocytes
chondroblasts replicate creating isogenous groups of chondrocytes
interstitial growth
new cartilage formed within existing cartilage
appositional growth
new cartilage formed at the surface of existing cartilage
Extracellular matrix of Bone
Mineralized with calcium phosphate (hydroxyapatitecrystals)
type I collagen (primarily)
proteoglycans
glycoproteins (osteonectin, osteopontin)
bone-specific Vitamin K-dependent (osteocalcin, protein S)
growth factors & cytokines
functions of bone
Structural support
Protection
Calcium regulation
Hemopoiesis
Osteons (Haversian)
Cylindrical structural units of bone
5 cell types in bone
Osteoprogenitor cells
Osteoblasts
Osteocytes
Bone-lining cells
Osteoclasts