Articular Cartilage & Synovial Fluid Flashcards
what are synoviocytes? - what do they produce?
what are the two types?
which is more?
how do the synoviocytes sit on subintima?
The synovial intimal cells, termed synoviocytes, are believed to be responsible for the production of synovial fluid components, for absorption from the joint cavity, and for blood/synovial fluid exchanges,
1-3 cell layer
•Type A: bone marrow derived macrophage for immune surveillance
•Type B: fibroblast-like connective tissue cell for proteoglycan production - more than type A
no barrier between synoviocytes & subintima !! - no basement membrane = no barrier for fluid movement !!!
what is subintima of synovial membrane / synovium characterised by?
a) type of CT?
b) capillaries?
what is subintima of synovial membrane / synovium characterised by?
a) type of CT: loose CT - type II collagen
b) capillaries: high capillary network - fenestrated capillaries (have basement membrane
esssentially, what is synovial fluid? [2]
synovial fluid:
ultrafiltrate of blood [1] with added hyaluronic acid [1]
which cells make hyaluronic acid for synovial fluid? [1]
which cells make hyaluronic acid for synovial fluid? [1]
type B synoviocytes
normal synovial fluid is WHAT? [1]
what does this mean regarding synovial fluid analysis [1]
normal synovial fluid is acellular
what does this mean regarding synovial fluid analysis [1]
if extract - should be able to read text behind, because it should just be fluid
what is hemarthrosis?
when tear / rupture fenestrated capillaries -> goes into synovial fluid bc theres no BM
which two components of synovial fluid interact to make glycoproteic gel of SF? [2]
interaction between hyaluronic acid & albumin: creates a tangled mesh that causes the glycoproteic gel - increases the viscosity
what is basic overview of RA?
- synovial membrane proliferates - gets thicker - 20/40 cell layers thick. subintima infiltrated with lympocytes
- synovial fluid has less protein
- *- HA damaged**
- together: causes SF to be less vicous
- white blood cell infiltration makes it cloudy from WHITE blood cells - lymphocytes
what does synovial fluid do? [1]
what does synovial fluid do? []
- coats the free spaces between articulating cartilage: keeps them sepearate!!!
- *Also seeps into articular cartilage at rest:** thickens the articular cartilage (like a sponge):
i) Slippery weight-bearing film which reduces friction between cartilage
ii) Distributes force across joint surfaces
iii) Forms reserve volume: when moving the joint, the SF is forced out & back into the joint
iv) Helps nourish articular cartilage
v) causes the HA and albumin to interact more and become my glycoproteic
describe hhow loading area / unloading area changes during movement / rest !!
as fluid part of SF moves into / out of the articular cartilage at rest / movement: what happens to the viscosity of the SF?
as fluid part of SF moves into / out of the articular cartilage at rest / movement: what happens to the viscosity of the SF? [1]
- *viscosity changes:** has non-newtonian flow characteristics:
- *i) at rest: gels**
ii) with movement: less viscous
what is structure of HA acid like?
•Repeated glucuronic acid and N-acetylglucosamine subunits
•0.2 to 10 million Daltons molecular weight
–Size & amount decreases with age
•Viscoelastic properties
•Powerful moisture binding - due to fact it is a GAG: draws in water !
how does the structure of SF respond to movement?
a) what is structure like at low / slow frequency movement?
b) what is structure like at high/ fast frequency movement?
how does SF respond to movement?
a) what is structure like at low / slow frequency movement: molecules align in direction of movement: energy dissipated as viscous flow
b) what is structure like at high/ fast frequency movement: entangled molecular network !! resists deformation & acts as shock absorbed
what is lubricin? [1]
what is structure like? [1]
function? [1]
lubricin: water soluble glycoprotein
structure: equal proportions of protein and oligosaccharides
function:
* *Forms thin superficial barrier [1]**
* *- Repels joint surfaces, preventing contact of articular surfaces [1]**
which cells produce lubricin? [2]
–Produced by chondrocytes and synoviocytes