Lecture 14 - Cartilage Flashcards
Outline what cartilage is ?
It is a type of connective tissue
it has cells called chondrocytes
an extracellular matrix of
Glycosaminoglycans - GAG’s
Hyaluronic acid
Type II collagen
Cartilage is avascular - relies on the diffusion of O2 and nutrients from the extracellular matrix
what are the three types of cartilage and their locations
only remember 1 location for each
• Hyaline–Most abundant
• Lining synovial joints –E.g. Shoulder, knee
• Nasal cartilages
• Costal cartilages
• Tracheal and laryngeal cartilages (exc. Epiglottis) •
type II collagen
Elastic–Same as hyaline but with added elastic fibres
• External ear
• Epiglottis
• Eustachian tube
Fibrocartilage– Also has abundant type I collagen fibres in addition to hyaline matrix
• Intervertebral discs
• Menisci of knee joint
• Pubic symphysis
what is the structure and purpose of hyaline cartilage
external Perichondrium –Dense CT
• Vascular and nervous supply to cartilage
• Fibroblast-like cells => Chrondroblasts=> Chondrocytes (appositional growth) Flattened chondrocyte towards edge
Rounder chondrocyte in its lacuna
Extracellular matrix: •
Type II collagen • GAGs, particularly hyaluronic acid– Creates a resistant hydrated gel
Bottom - Isogenous nests of newly divided chondrocytes (interstitial growth) - sit in lacunae (lake)
cells divide and flatten as they move to surface secreting ECM to separate themselves
O2 diffuses from surface downwards to the newly dividing chondrocytes
hyaline cartilage is the precursor for model bones in fetal development
growth is inwards (appositinal growth)
forms the tacheal wall - c shaped - provents collapse from vaccum
what do chondrocytes do ?
produce ECM - GAG’s ect in response to stimuli
what form of cartilage is in the synovial joint , why ?
a highlt mobile joint
Hyaline lines opposed edges of the bone
articular cartilage lines the surfaces of the bone
synovial fluid is produced by synovial membrane, to fill joint cavity with synovial fluid
the joint is stabilised by the fibrous joint capsule - continuous with peritoneum of bone
ligaments and muscles
acts as impact absorber/ shock absorber
prevents bone/ bone grinding
what is osteoarthritis ?
degeneration and failure of articular cartilages
bone bone rubbing causes inflammation and pain
what is rheumatoid arthritis
Autoimmune disease - rhuematoid factor produced by B lymphocytes
inflammation of the synovium and thickening of the joint capsule
compare rhematoid arthritis and osteoarthritis
Osteo - Degenerative disease stiff in morining for 30 mins cartillage loss it is asymettrical heberdens nodes
rheumatoid - autoimmune inflammed synovium symmetrical stiffness lasts longer extra articular involvement
what is elastic cartilage ?
only chondrocytes like hyaline
Does not calcify with ageing unlike hyaline
rich in elastic fibers - so elastic
similar structure, perichondrim of flat condrocytes at top
what is fibrous cartilage ?
NO perchondrium
contatins chondrocytes and fibroblasts that secret type 1 collagen
cells distribute in rows and isogenious nests
chondrocytes are elongated
