joint articular tissues Flashcards
modulates chondrocyte metabolism
mechanical stimulation
classic description of cartilage?
avascular, aneural, alymphatic
how cartilage receives nutrients, oxygen?
diffusion
pH of cartilage?
7.4
articular cartilage composition?
water 65-80%
collagen 10-20%
proteoglycans 10-15%
chondrocytes 5%
cartilage collagen type?
95% type II (IV, V, VI, IX, X, XI)
effect of osteoarthritis?
INCREASED water content
proteoglycans function?
trap and hold water via cartilage pores
subunits of proteoglycans?
GAGs: chondroitin sulfate, keratin sulfate
cartilage layer with highest collagen fiber concentration?
tangential-superficial zone
coefficient for friction in human joint?
0.002-0.04
predominant type of lubrication in dynamic joint function?
elastohydrodynamic lubrication
effect of aging?
DECREASED WATER content
INCREASED PROTEIN content
effect of immobilization?
cartilage degeneration
vascularized, mediates nutrient exchange
synovium
synovium cell type A
for phagocytosis
synovium cell type B
produce synovial fluid
synovial fluid function?
lubricates, provides nourishment
‘nonnewtonian’ flow characteristics of synovial fluid?
viscosity not constant; increases as shear rate increases (c/o lubricin)
meniscus function?
deepens articular surface, broadens contact area, distributes load
knee meniscus function?
transmits 50% force in extension, 90% in deep flexion
blood supply of knee meniscus?
geniculate arteries (only to PERIPHERAL zone)
meniscal tear with best healing characteristics?
peripheral, acute, rim width > 4mm
collagen type in meniscus?
primarily type I
