Cartilage Flashcards
Where do we find cartilage?
- Embryo: skeleton intially mostly cartilage, bones replace during fetal development/childhood
- Adult: skeleton (e.g. costal cartilage (hyaline) in ribcage), nose, external ear, trachea and larynx
What is cartilage (structure, function, characteristics)?
- Semi-rigid, flexible connective tissue
- Support in tissues/organs and scaffolding for bone development
- Avascular and aneural - obtains nutrition by long range diffusion from blood vessels on its periphery
- High-mechanical strength
What is cartilage composed of?
CT so:
1. Cells - chondroblasts and chondrocytes
2. ECM - water, mixture of molecules, fibres
What are the 3 types of cartilage?
- Hyaline
- Elastic
- Fibrocartilage
Where can hyaline cartilage be found
Articular, costal and nasal cavities, larynx, trachea, bronchi and epiphyseal growth plates
What is the appearance of hyaline cartilage and how strong is it?
Glassy appearance - weakest type of cartilage
How do the different types of carticalge differ from each other?
In compostion of ECM and number of cells
What is the composition of hyaline cartilage like?
type II collagen fibres, proteoglycans, glycoproteins, and extracellular fluid. + chondrocytes (cells)
Where is elastic cartilage found
external ear, larync and epiglottis (maintains shape)
What are some features of elastic cartilage
Flexible but resistant
What does elastic cartilage contain?
Chondrocytes, elastic and collagen fibres, matrix is composed of glycosaminoglycans, proteoglycans and multiadhesive glycoproteins
Where is fibrocartilage found?
In joint capsules, ligament/tendon insertions (into bone) and intervertebral discs
What is the composition of fibrocartilage
Chondrocytes + Alternating layers of hyaline cartilage matrix and dense bundles of (type 1) collagen fibres - no perichondrium
What is the perichondrium
a dense layer of fibrous connective tissue that covers the surface of most of the cartilage in the body. The perichondrium consists of an outer fibrous layer that contains fibroblasts and an inner chondrogenic layer that contains chondroblasts.
How strong is fibrocartilage
Strongest type
What are the properties of cartilage in terms of blood supply and how does this affect cartilage’s structure?
Avascular (although carticage channels = pores from B-vessels into cartilage matrix), and since most cells distant from vascular supply, diffusion must occur from surface (perichondrial) vessels to cells. - Cartilage thus is limited to a few mm thick and does not regenerate well/at all (no O2/nutrients)
Articular cartilage
Type of hyaline cartilage: smooth, white tissue that covers the ends of bones where they come together to form joints. Obtains its nutrients from synovial fluid, but doesn’t heal itself well so damage/wear and tear causes it to degrate and stop smooth movement of bones
What can happen to carticage in terms of ageing
Water content dec:
- dec shock absorption
- less protection of articular surfaces —> inc risk of damage
Which cartilage types have a perichondrium
Hyaline and elastic
Chondrocytes
Chondrocytes are the cells responsible for cartilage formation, and they are crucial for the process of endochondral ossification, which is useful for bone development. - mainly responsible for the production of collagen and the extracellular matrix that will lead to the maintenance of cartilaginous tissues within joints.
- only cells found in healthy cartilage
how do the 3 types of cartilage differ
In relative amounts of callagen, elastic fibres and ground substane/matrix
