what kind of tissue is the capsule composed of?
dense, irregular CT and has a lot of nerves, vessels, and mechanoreceptors here
2 layers of synovium
intima and stroma
intima tissue cell type
synoviocytes
function of intima
to produce synovial fluid (done by synoviocytes) and to phagocytose joint debris
stroma tissue type
loose or dense irregular CT
what does stroma tissue blend with?
the fibrous joint capsule
specific function of macrophages in the stroma layer
to keep the synovial fluid clean of debris
cell population of stroma tissue
macrophages, lymphocytes, and mast cells
function of the joint capsule
to respond to mechanical loading via mechanoreceptors and stability of the joint (proprioception), as well as stability and vessel/nerve supply
ligaments and capsule relationship
capsules blend in with the capsule
free nerve endings
are responsible for transmitting messages of temperature, mechanical stimuli, or pain
what do sensory nerves respond to in cartilage?
stretch, tension, and pressure
example of sensory nerves in cartilage
pacinian corpuscles
tendons vs capsule
tendons have more regular tissue (parallel lines) than capsules do to help with force distribution better
main cell type of articular cartilage
chondrocytes
chondrocytes function
maintain ECM by producing glycosaminoglycan and shock absorption and gliding movement
glycosaminoglycan
absorb water and act as shock absorbers in articular cartilage
main collagen type in articular cartilage
type II
tide marks
represent the point at which calcification in cartilage occurs and is sort of like an insertion point of cartilage to bone (to the end plate)
osteochondral junction
is where the collagen fibres from the radial zone insert directly to the bone
OA relationship to osteoporosis
osteoporosis is actually protective against OA due to having spongier and less dense bone, thus diffusing the stress distributed to the cartilage (shock absorption)
what part of bone is made of cartilage?
the physis
osteochondrosis
is when the cartilage of bone can become inflamed due to overuse (is a group of disorders affecting bone)
healing capacity of cartilage
is very limited due to a lack of vessels