What do chondrocytes do?
- Produce and maintain the extracellular matrix
What is cartilage?
- An avascular tissue that consists of an extensive extracellular matrix in which lie chondrocytes
What is there a high ratio of in the collagen matrix?
- High ratio of glycosaminoglycans to type II collagen
- Permits ready diffusion of substances from the chondrocytes to the blood vessels surrounding the cartilage
How does the structure of the extracellular matrix relate to its function?
- Solid and firm, but also pliable and has a high amount of hyaluronic acid
- Therefore resilient to the repeated application of pressure
Describe the ground substance of cartilage
- Hyaluronic acid molecules forming linear aggregates are interwoven with collagen fibrils
- Hyalouronic acid molecules have proteoglycan monomers attached, which themselves are made up of a core protein and glycosaminoglycan units
- The GAGs a are negatively charged, so attract water, forming a hydrated gel
What types of cartilage are there?
- Hyaline
- Elastic
- Fibrocartilage
Describe the structure of hyaline cartilage
- the matrix contains hyaluronic acid, proteoglycans and type III collagen
- The hyalouronate proteoglycan aggregates are bound to the fine collagen matrix fibres
Describe the structure of elastic cartilage
- Has a matrix like hyaline cartilage, but also contains many elastic fires and elastic lamellae
Describe the structure of fibrocartilage
- Contains matrix materials as in hyaline cartilage, and is also abundant in Type I collagen fibres
What types of cells are present in hyaline cartilage?
- Chondrocytes only
- Present singly or in clusters of isogenous groups if recently divided
Where does hyaline cartilage occur?
- Articulating surfaces
- Parts of the ribcage
- Nose
- Larynx
- Trachea
- Bronchi
What is pericondrium?
- A layer of dense connective tissue that is at the edges of hyaline cartilage
- Contains fibroblast like cells which develop into chondroblasts and then into chondrocytes
What is appositional growth?
-Growth from the periphery
What is interstitial growth?
- Growth between divided chondrocytes in isogenous groups as matrix is laid down
What is the difference between territorial matrix and interterritorial matrix?
- Territorial is darker as is more highly sulphate do
- Interterritorial is lighter
