68 Questions
What is the main component of the cartilage in diarthrodial joints?
Type 2 collagen
What is the role of synovium in diarthrodial joints?
Lines the joint and secretes synovial fluid
Why does hyaline articular cartilage appear radiolucent on X-ray?
It is non-calcified
What happens to the bones in a joint when the hyaline articular cartilage is worn out?
They touch each other
What is the main source of nutrients for hyaline articular cartilage?
Synovial fluid and subchondral bone
Which enzyme targets the type 2 collagen arcade?
MMP 1
In osteoarthritis (OA), which enzyme targets proteoglycans?
MMP 3
What upregulates MMP enzymes in osteoarthritis?
Plasmin
Which enzyme targets collagen and is considered a collagenase?
MMP 13
What inhibits the action of MMP enzymes in normal cartilage?
TIMPS
What stimulates cartilage metabolism and synthesis?
Insulin like growth factor
What is the main function of proteoglycans in cartilage?
Maintain cartilage hydration
Which component of the proteoglycan is responsible for determining where glycosaminoglycans will be added?
Core protein
What happens to water content in the articular cartilage during loading and unloading of joints?
Water content fluctuates with each step taken
In what region of the proteoglycan core protein is chondroitin sulfate (CS) located?
Distal carboxyl end
What is the main effect of glycosaminoglycans (GAGs) being negatively charged?
Allow for water absorption and cartilage deformability
Which statement best describes the role of aggrecans in the cartilage matrix?
Maintain water content and prevent enzymatic degradation
Why are proteoglycan aggregates described as 'prisoners' in the collagen network?
Due to their large molecular weight and hydrophilicity
Which type of GAG chain is enriched in glucosamine?
'Keratan' sulfates (KGS)
'Regression to a more fetal type molecule' in osteoarthritis refers to a reversion to which chondroitin sulfate form?
'Chondroitin 4 sulfate (C-4S)'
'Synovial space' is a region where water is released by _____________ into during loading of joints.
Proteoglycans (PGs)
What is the main function of the type 2 collagen in hyaline articular cartilage?
Giving the cartilage its tensile strength
What is the main role of proteoglycans (PGs) in hyaline articular cartilage?
Attracting water into the cartilage
In osteoarthritis, what happens to the chondrocytes within the lacunae?
They undergo mitoses in brood capsules
What is the reason behind the deformability of hyaline articular cartilage?
Proteoglycans with negatively charged glycosaminoglycans (GAGs)
What happens to proteoglycan aggregates when the collagen network is broken down?
Aggregates escape into the synovial space
Which statement correctly describes the role of chondrocytes in osteoarthritis?
They multiply in brood capsules within lacunae
Why is water content vital for the structure of hyaline articular cartilage?
To maintain compliance and deformability
How do proteoglycans in hyaline articular cartilage attract water?
Due to their negatively charged glycosaminoglycans (GAGs)
What is the primary role of chondrocytes in normal hyaline articular cartilage?
Maintaining the articular matrix and synthesizing matrix molecules
Why is it important to have a hook region on proteoglycans (PGs)?
To allow multiple PG subunits to attach to hyaluronic acid
What is the main structural component of hyaline articular cartilage?
Type 2 collagen
What is the primary source of nutrients for chondrocytes in hyaline articular cartilage?
Synovial fluid
What maintains the radiolucent appearance of hyaline articular cartilage on X-ray?
Calcification
Where do tendons and ligaments attach to bone in the body?
Entheses
What causes bones to appear to be touching due to the loss of the spacer effect in arthritis?
Joint space narrowing
What is the function of synovium in diarthrodial joints?
Nutrient supply to cartilage
What happens to the reparative capacity of hyaline articular cartilage once it wears out?
It decreases significantly
What are the two main components of articular cartilage?
(Correct) Type 2 collagen and proteoglycans
How does hyaline articular cartilage obtain its nutrients?
(Correct) From synovial fluid and subchondral bone
Why does hyaline articular cartilage look radiolucent on X-ray?
It is non-calcified.
What is the main function of the type 2 collagen in hyaline articular cartilage?
Holding proteoglycans in check
What is the primary role of chondrocytes in normal hyaline articular cartilage?
Maintaining the articular matrix
What are the properties of hyaline articular cartilage?
Ability to withstand impact with tensile strength
What is the reason behind the deformability of hyaline articular cartilage?
Proteoglycans' water-attracting properties
In osteoarthritis (OA), which enzyme targets proteoglycans?
Aggrecanase
'Synovial space' is a region where water is released by _____________ during loading of joints.
Proteoglycans
'Regression to a more fetal type molecule' in osteoarthritis refers to a reversion to which chondroitin sulfate form?
"Dermatan sulfate"
What stimulates cartilage metabolism and synthesis?
Matrix metalloproteases (MMPs)
What inhibits the action of MMP enzymes in normal cartilage?
Type 2 collagen network breakdown
Which enzymes are considered the 'villains' in the context of hyaline articular cartilage degradation?
Matrix metalloproteases (MMPs)
What is the main target of stromelysin, also known as MMP 3?
Proteoglycans
What upregulates the neutral matrix metalloproteases (NMMPs) according to the text?
IL-1 and plasmin
In osteoarthritis, which enzyme targets the collagen arcade specifically?
Collagenase 13
What inhibits and blocks the metalloprotease enzymes in normal hyaline articular cartilage?
TIMPs
Which enzyme targets proteoglycans in the context of osteoarthritis?
MMP 3
What is considered a characteristic of normal chondrocytes in hyaline articular cartilage?
-
- MMP enzyme activity
'Nasty' MMPs in osteoarthritis include which specific enzymes?
(P)MMP 1 and MMP 13
What stimulates cartilage metabolism and synthesis according to the text?
Insulin-like growth factor and growth hormone
Which enzyme is responsible for targeting PGs, or proteoglycans?
MMP 3
What is the primary function of hyaline articular cartilage proteoglycans?
Protection from metallo proteases
Where are the glycosaminoglycan (GAG) side chains attached in the proteoglycan monomers?
To the core protein
Why are proteoglycan aggregates described as 'prisoners' in the collagen network?
To protect them from enzymatic degradation
What is the main component responsible for attracting water into hyaline articular cartilage?
Glycosaminoglycans (GAGs)
In which region of the proteoglycan core protein is keratan sulfate (KS) located?
Proximal or amino-terminal
What effect do glycosaminoglycans (GAGs) being negatively charged have on hyaline articular cartilage?
Increases deformability
'Regression to a more fetal type molecule' in osteoarthritis refers to a reversion to which form of chondroitin sulfate?
(C-4S) Chondroitin 4 sulfate
What is the primary role of the hyaluronic acid binding region (HABR) in proteoglycan aggregates?
Binding to HA strands
Learn about the structure of cartilage and the components of the aggrecan PG monomer, including the core protein. Understand how the structure allows for deformability and shock absorption in cartilage.
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