make synovial fluid, add hyaluronan for lubrication of soft tissues, and connect the joint to the systemic circulation for healing and messaging
The function of articular cartilage. (2)
absorb compression and provide a tough, resilient, lo friction surface
The function of subchondral bone.
provide a hard underpinning surface that can transition the forces from cartilage to bone
Joints must... (3)
be lubricated, absorb impact, provide metabolites to articular cartilage
The articular cartilage surface resists _______ and the depth resist ___________.
The synovial membrane makes __________ plus adds ________.
fluid dialysate of plasma; hyaluronan
Subchondral bone provides resistance to ___________.
Composition of the fibrous joint tissue... (2)
type I collagen, proteoglycan
Wolfe's law describes how the ______________ becomes ____________.
subchondral bone plate; denser
The articular cartilage remains turgid by harboring ____________.
Repair cartilage is type _____, which is not as strong as the type ___ that was there before injury.
Component of articular cartilage that provides resistance to compression.
Component of articular cartilage that provides resistance to shear.
type II collagen
_____________ are attached to the core protein in articular cartilage; the core protein attaches to ___________.
Glycoaminoglycans (GAGs); hyaluronan
Proteoglycan aggregates are turgid and therefore resist __________.
What type of cartilage defects do not heal?
What type of cartilage defects heal and why?
full thickness cartilage defects because all the cartilage is gone, the bone, bleeds, and this allows healing
What are 3 positive effects of exercise for joint health?
more proteoglycan, more type II collagen, more mature repair tissue
What is the subchondral bone micropik technique?
allows improved healing of full thickness defects by allowing more blood to enter joint
In remodeling, _____________ precedes ____________.
bone resorption; bone deposition
Mineralized cartilage has similar consistency to bone but lacks ___________.
vessels (does not bleed when cut)
___________ turnover in cartilage is slight, but ____________ turnover is high.
A subtle thickening and softening of cartilage due to loss of proteoglycans.
In the earliest stage of chondromalacia, there is an ________ in water in the matrix; due to the increased loss of __________, water content ____________.
increase; proteoglycans; progressively decreases
With erosion, there is initially decreasing _____________ content in the cartilage, thus decreasing binding ____________, causing ___________; this cartilage is less resistant to __________, and __________ are lost.
proteoglycans; water; degeneration; shearing; superficial layers of cartilage
With fibrillation, there is continuing loss of _____________ and ____________, causing the collagen fibers in the _________ to _____________.
matrix proteoglycans; water; radial layer; condense and split
Death of chondrocytes that can be present from erosion through ulceration stages.
A chondrone is an ineffectual _____________ of remaining chondrocytes.
Ulceration is the wearing off of cartilage to the level of the _________ or __________.
tidemark; subchondral bone
Sclerosis in the subchondral bone with its surface polished smooth due to wear in areas of ulceration.
Chondro-osseous proliferation within the synovial membrane or at synovial junctions.
Osteophyte formation is likely due to... (2)
mechanical forces due to joint instability; anabolic cytokines (TGF β)
With modeling of cartilage and subchondral bone, ___________ through the ____________ will allow this layer to undergo endochondral ossification and model.
microcracks; mineralized layer of cartilage
Modeling of cartilage and subchondral bone occurs due to ________________.
altered mechanical use
________________ may be a significant factor in joint stiffness with DJD.
Fibrosis of joint capsule
Fibrosis of the joint capsule could result in contracture due to ___________ or ____________.
lack of use; increased fibrosis from anabolic cytokine expression (TGF β)
Very early in disease due to release of sterile joint antigens.
lymphoplasmacytic synovitis with synovial hyperplasia
Bony fusion of a joint.
Ankylosis across the joint space occurs by...
direct bony fusion of ulcerated surfaces.
Ankylosis around the joint space occurs due to...
fusion of osteophyte formations at the margins of the joint.
Subchondral bone cysts are cavities lined by __________ in the subchondral bone in advanced stages of ______; they are possibly secondary to the __________ of synovial fluid dissecting into subchondral bone via ______________.
synovium; DJD; pressure; full thickness fissures in cartilage
DJD is caused by anything that will injure _________ and/or reduce __________, therefore, decreasing ___________ and ___________.
chondrocytes; proteoglycans; water; resistance to wear
3 causes of DJD.
aging chondrocytes, injury to synovial cells/chondrocytes, subchondral bone sclerosis
Aging chondrocytes can cause DJD because...
they have decreased proteoglycan synthesis.
Injury to synovial cells/chondrocytes causes ________, which induced increased __(3)__; these substances decrease __________ synthesis and activate __________, causing DJD.
Necrosis/degeneration of chondrocytes can contribute to infectious inflammation of joints because there is failure to maintain _____________ and ________ of the matrix, leading to ___________.
proteoglycans; collagen; enzymatic destruction
Necrosis/degeneration of synoviocytes can contribute to infectious inflammation of joints because there is failure to ________________, causing injury to _________.
lubricate and nourish cartilage; chondrocytes
Fibroblasts in reactive synovial tissue can ______________ to produce _________ that are lytic to cartilage; does NOT occur in DJD, only infectious inflammation of joints.
grow into articular cartilage (pannus formation); MMPs
Infectious inflammation of joints can lead to _________; synovial damage leads to decreased _________ and _________; incongruous surfaces lead to decreased ___________ and __________; loss of chondrocytes leads to inadequate _________ and activation of _________.