Cartilage Flashcards
what is cartilage made from
Strong, flexible, semi-rigid supporting tissue made of chondroblasts + chrondrocytes, suspended in an extracellular matrix (10% aggrecan, 75% water and a mix of collagen and others)
what are the 3 types of cartilage
elastic cartilage
fibrocartilage
hyaline cartilage
what are examples of elastic cartilage
external ear and epiglottic
what is an example of fibrocartilage
intravertebral discs
what are examples of hyaline cartilage
articular surface of synovial joints (hip, knee, shoulder)
what are properties of elastic cartilage
flexible/resilient
what are constituents of elastic cartilage
Elastic fibres as well as collagen fibres
Surrounded by perichondrium
what are properties of fibrocartilage
its the strongest type
what are constituents of fibrocartilage
Alternating layers of hyaline cartilage matrix and thick layers of dense collagen fibres oriented in the direction of fucntional stresses
No perichondrium
Transitional latyer between hyaline cartilage and tendon/ligament
what are the properties of elastic cartilage
Weakest type
Redistributes force and reduces friction
Avascular, aneural, alymphatic, non-immunological
Nourished by synovial fluid
what are constituents of elastic cartilage
Widely dispersed fine collagen fibres (Type 2) which strengthens it
Has perichondrium
Organised in layers
what are different layers of elastic cartilage
Zone 1 - ‘gliding zone’ collagen fibres run parallel to resist shearing
Does some phagocytosis and has inflammatory characteristics to act as a barrier
Zone 2 – transitional zone
Obliquely arranged collagen
Transition from zone 1 that resists shearing and zone 3 that resists compression
Zone 3 – deep/radial zone
Thickest layer
Perpendicular collagen fibres
Resists compression
Tidemark
Boundary between calcified and uncalcified cartilage
Cartilage is attached to subchondral bone by hydroxyapatite crystals
whats the main cellular constituents of cartilage
chondrocytes
how does cartilage heal
Superficial injuries (above the tidemark (zone 3)) do not heal
Deep injuries to subchondral bone result in haematoma, fibrin clot and an inflammatory response – this forms fibrocollagen (type1) which has none of the same functional properties
Infection can be devastating
Bacteria release proteases and the hosts inflammatory repsonse can hydrolyse cartilage and dead cells, hen produced more destructive enzymes
