38 Questions
What is the main type of collagen found in fibrocartilage?
Type 1 collagen
Which type of joint has hyaline articular cartilage with type 2 collagen and aggregated proteoglycans?
AMPHI arthroses
What is the main characteristic of diarthrodial joints?
They have poor reparative capacity
Which component of joints does not regenerate once worn out?
Hyaline articular cartilage
In which type of joint is the cartilage comprised of thin interlocking fibrous tissue?
SYN arthroses
What type of mobility is characteristic of AMPHI arthroses?
Minimal mobility
Which joint has fibrocartilage composed mainly of type 1 collagen?
Symphysis pubis
What is the main function of articular cartilage?
To act as a shock absorber in joints
What confers deformability and the ability to distribute load in a reversible sponge-like fashion to hyaline articular cartilage?
Proteoglycans with negatively charged glycosaminoglycans (GAGs)
What gives hyaline articular cartilage its strength and structure?
Type 2 collagen
Where are the chondroitin sulfate (CS) rich region and keratan sulfate (KS) rich region located on the proteoglycan (PG) core protein?
CS at the superior aspect and KS at the proximal end
In osteoarthritis, what happens to the chondrocytes in hyaline articular cartilage?
They multiply and try to synthesize more matrix molecules
What is the main function of the hyaluronic acid binding region (HABR) in the proteoglycan (PG) monomer?
To bind to hyaluronic acid (HA)
What causes joint space narrowing in arthritis?
Wear and tear of articular cartilage
What is the function of aggrecan in forming proteoglycan (PG) aggregates?
To aggregate with hyaluronic acid (HA)
What is the main contributor to the deformability and compliance of articular cartilage?
Water content
Which part of the proteoglycan (PG) subunit determines where and which glycosaminoglycans (GAGs) will be added on?
Core protein
Which component of proteoglycans attracts water into the cartilage?
Glycosaminoglycans
What happens to cartilage when there are no GAGs in proteoglycans?
It becomes rigid and brittle
What is the consequence of breakdown of the collagen network in hyaline articular cartilage?
Loss of proteoglycan aggregates into the synovial space
What is the function of aggrecan PG monomers in forming PG aggregates?
To increase cartilage hydration
How do chondrocytes receive nutrients in hyaline articular cartilage?
From subchondral bone underneath the cartilage
Which part of the proteoglycan monomer resembles a hook allowing it to bind with hyaluronic acid (HA)?
Hyaluronic acid binding region (HABR)
What is the main reason that proteoglycan (PG) aggregates are protected from enzymatic degradation?
Their negative charge makes them hydrophilic and bulky
What is the role of tissue inhibitors of metalloproteases (TIMPs) in the context of osteoarthritis (OA)?
They block the MMP enzymes responsible for cartilage degradation
Which enzyme targets the type 2 collagen arcade in cartilage?
Collagenase 1 or MMP 1
In osteoarthritis (OA), which enzyme specifically targets proteoglycans?
MMP 3
What happens to the water content in articular cartilage during late osteoarthritis?
It decreases leading to dried dessicated PG aggregates
Which factor upregulates the production of MMP enzymes that contribute to cartilage degradation?
Interleukin-1 (IL-1)
What is the main difference between normal chondrocytes and those in osteoarthritis (OA)?
'Chondrocytes in OA exhibit intense uptake of metachromatic staining'
What is the main cause of the worse fragmentation of collagen arcade in osteoarthritis (OA)?
Fragility of collagen network due to collagenases MMP 1 and 13 being up-regulated
What happens to the water content in cartilage in later stages of OA?
Decreases due to drying of cartilage
What is the impact of decreased proteoglycan (PG) aggregates in osteoarthritis?
Regression to fetal CS-4 instead of CS-6
What is a notable finding common in both aging and osteoarthritis?
Increased apoptosis and ER stress
What leads to milder non-progressive fibrillation of cartilage?
Lack of hydrophilic GAGs
Which enzyme is responsible for cleaving PG aggregates in osteoarthritis?
Aggrecanase
In osteoarthritis, what causes the regression of chondroitin sulfate from CS-6 to CS-4?
Cleavage at the CS-6 hook binding region
What effect does ER stress have on cartilage in aging and osteoarthritis?
ER stress makes cartilage more susceptible to changes
Test your knowledge on the properties of hyaline articular cartilage, including its tensile strength derived from the type 2 collagen arcade. Learn about PG aggregates, AGGRECANS, and their ability to aggregate with hyaluronic acid in this quiz.
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