Cartilage

• Skeletal Cartilage

  skeletal cartilage = made up of some variety of cartilage tissue scuplted to fit its body location + function

  consists primarily of water

  has the ability to spring back to its OG shape after being compressed
• General Structure of Cartilage

  contains no nerves/blood vessels

  surrounded by a layer of dense irregular connective tissue = perichiondrium
• Perichondrium

  the layer of dense irregular connective tissue that surrounds cartilage

  acts as reinforcemet to resist outward expansion when the cartilage is compressed

  also contains blood vessels that nourish the cartilage cells

  the thickness of cartilage is limited by the distance nutrients can diffuse thru the matrix to reach the cells
• Types of Cartilage

  3 types of cartilage:

  hyaline

  elastic

  fibrocartilage
• Common Components of Cartilage

  all 3 types have the same basic components

  = cells called chondrocytes, encolsed in small cavities (lacunae) w in an extracellular matrix (made by chondroblasts) containing a jelly-like ground substance + fibres
• Hyaline Cartilage

  provides support w flexibility + resilience

  the most abundant skeletal cartilage

  chondrocytes r spherical (specific)

  the only fibre type in their matrix = fine collagen fibres
• Types of Hyaline Cartilage

  articular cartilage

  costal cartilage

  respiratory cartilage

  nasal cartilage
• Hyaline Cartilage - Articular

  articular cartilage = cover the ends of most bones at movable joints
• Hyaline Cartilage - Costal

  costal cartilage = connect the ribs to the sternum (breastbone)
• Hyaline Cartilage - Respiratory

  respiratory - form the skeleton of the larynx (voice box) + reinforce other respiratory passageways
• Hyaline Cartilage - Nasal

  nasal cartilage = supports the external nose
• Elastic Cartilage

  resemble hyaline cartilage but contain more stretchy elastic fibres = able to stand up to repeated bending

  found in 2 skeletal locations - external ear + epiglottis (the flap that bends to cover the opening of the larynx each time we swallow)
• Fibrocartilages

  highly compressible w great tensile strength

  consist of roughly parallel rows of chondrocytes alternating w thick collagen fibres

  occur in sites that r subjected to both pressure + stretch - the padlike cartilages (mensici) of the knee + the discs between vertebrae)
• Growth of Cartilage

  unlike bone, which has a hard matrix, cartilage has a flexible matrix that can accomodate mitosis

  it is the ideal tissue to use to rapidly lay down the embryonic skeleton + to provide for new skeletal growth
• Appopositional Growth of Cartilage

  cartilage-forming cells in the surrounding oerichondrium secrete new matrix against the external face of the existing cartilage tissue
• Interstitial Growth of Cartilage

  the lacunae-bound chondrocytes (cavity-bound) divide + secrete new matrix, expanding the cartilage from w in

  typically, cartilage growth ends during adolescence when the skeleton stops growing