Cartilage Flashcards
Where is cartilage found in embryos?
- skeleton initially mostly cartilage
- bone replaces cartilage during fetal development & childhood
- more prevalent than in adults
Where is cartilage found in adults?
- skeleton (e.g. costal cartilage)
- nose
- external ear
- trachea & larynx
What is cartilage?
- semi-rigid, flexible connective tissue
- support in tissues & organs & scaffold for bone development
- avascular & aneural, obtains nutrition by long range diffusion from blood vessels on its periphery
- high mechanical strength
What makes up cartilage?
Cells — chondroblasts and chondrocytes
ECM — roughly 75% water, mixture of molecules and fibres
What are the three types of cartilage?
1.) hyaline (most common type including articular cartilage)
2.) elastic (e.g. in the external ear)
3.) fibrocartilage (e.g. intervertebral discs)
Where is hyaline cartilage found?
Articular, costal & nasal, also in larynx, trachea, bronchi & epiphyseal growth plates
What are some characteristics of hyaline cartilage?
- glassy appearance
- weakest type of cartilage
Where is elastic cartilage found?
In external ear, larynx & epiglottis (helps to maintain their shape)
What are the characteristics of elastic cartilage?
- flexible & resilient
- contains elastic as well as collagen fibres
Where is fibrocartilage found?
In joint capsules, ligaments, tendon insertions & intervertebral discs
What are the characteristics of fibrocartilage?
- alternating layers of hyaline cartilage matrix and dense bundles of collagen fibres
- strongest type of cartilage
What are cartilage channels?
Pores from blood vessels into cartilage matrix
Describe nutrition of cartilage
- usually described as avascular
- however, most cells are distant from vascular supply so use diffusion from surface (perichondrial) vessels
- articular cartilage obtains nutrients via synovial fluid
What happens when cartilage ages?
- water content of cartilage decreases
- reduced shock absorption
- less protection of articular surfaces & increased risk of damage
