Cartilage Structure and Aggrecan PG Monomer
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Questions and Answers

What is the main component of the cartilage in diarthrodial joints?

  • Type 2 collagen (correct)
  • Type 4 collagen
  • Type 1 collagen
  • Type 3 collagen

    • What is the role of synovium in diarthrodial joints?

  • Provides blood supply to the cartilage
  • Lines the joint and secretes synovial fluid (correct)
  • Forms the fibrous capsule around the joint
  • Produces chondrocytes for cartilage regeneration

    • Why does hyaline articular cartilage appear radiolucent on X-ray?

  • It is non-calcified (correct)
  • It is calcified
  • It has a thick structure
  • It is made up of type 1 collagen

    • What happens to the bones in a joint when the hyaline articular cartilage is worn out?

    <p>They touch each other</p> Signup and view all the answers

    What is the main source of nutrients for hyaline articular cartilage?

    <p>Synovial fluid and subchondral bone</p> Signup and view all the answers

    Which enzyme targets the type 2 collagen arcade?

    <p>MMP 1</p> Signup and view all the answers

    In osteoarthritis (OA), which enzyme targets proteoglycans?

    <p>MMP 3</p> Signup and view all the answers

    What upregulates MMP enzymes in osteoarthritis?

    <p>Plasmin</p> Signup and view all the answers

    Which enzyme targets collagen and is considered a collagenase?

    <p>MMP 13</p> Signup and view all the answers

    What inhibits the action of MMP enzymes in normal cartilage?

    <p>TIMPS</p> Signup and view all the answers

    What stimulates cartilage metabolism and synthesis?

    <p>Insulin like growth factor</p> Signup and view all the answers

    What is the main function of proteoglycans in cartilage?

    <p>Maintain cartilage hydration</p> Signup and view all the answers

    Which component of the proteoglycan is responsible for determining where glycosaminoglycans will be added?

    <p>Core protein</p> Signup and view all the answers

    What happens to water content in the articular cartilage during loading and unloading of joints?

    <p>Water content fluctuates with each step taken</p> Signup and view all the answers

    In what region of the proteoglycan core protein is chondroitin sulfate (CS) located?

    <p>Distal carboxyl end</p> Signup and view all the answers

    What is the main effect of glycosaminoglycans (GAGs) being negatively charged?

    <p>Allow for water absorption and cartilage deformability</p> Signup and view all the answers

    Which statement best describes the role of aggrecans in the cartilage matrix?

    <p>Maintain water content and prevent enzymatic degradation</p> Signup and view all the answers

    Why are proteoglycan aggregates described as 'prisoners' in the collagen network?

    <p>Due to their large molecular weight and hydrophilicity</p> Signup and view all the answers

    Which type of GAG chain is enriched in glucosamine?

    <p>'Keratan' sulfates (KGS)</p> Signup and view all the answers

    'Regression to a more fetal type molecule' in osteoarthritis refers to a reversion to which chondroitin sulfate form?

    <p>'Chondroitin 4 sulfate (C-4S)'</p> Signup and view all the answers

    'Synovial space' is a region where water is released by _____________ into during loading of joints.

    <p>Proteoglycans (PGs)</p> Signup and view all the answers

    What is the main function of the type 2 collagen in hyaline articular cartilage?

    <p>Giving the cartilage its tensile strength</p> Signup and view all the answers

    What is the main role of proteoglycans (PGs) in hyaline articular cartilage?

    <p>Attracting water into the cartilage</p> Signup and view all the answers

    In osteoarthritis, what happens to the chondrocytes within the lacunae?

    <p>They undergo mitoses in brood capsules</p> Signup and view all the answers

    What is the reason behind the deformability of hyaline articular cartilage?

    <p>Proteoglycans with negatively charged glycosaminoglycans (GAGs)</p> Signup and view all the answers

    What happens to proteoglycan aggregates when the collagen network is broken down?

    <p>Aggregates escape into the synovial space</p> Signup and view all the answers

    Which statement correctly describes the role of chondrocytes in osteoarthritis?

    <p>They multiply in brood capsules within lacunae</p> Signup and view all the answers

    Why is water content vital for the structure of hyaline articular cartilage?

    <p>To maintain compliance and deformability</p> Signup and view all the answers

    How do proteoglycans in hyaline articular cartilage attract water?

    <p>Due to their negatively charged glycosaminoglycans (GAGs)</p> Signup and view all the answers

    What is the primary role of chondrocytes in normal hyaline articular cartilage?

    <p>Maintaining the articular matrix and synthesizing matrix molecules</p> Signup and view all the answers

    Why is it important to have a hook region on proteoglycans (PGs)?

    <p>To allow multiple PG subunits to attach to hyaluronic acid</p> Signup and view all the answers

    What is the main structural component of hyaline articular cartilage?

    <p>Type 2 collagen</p> Signup and view all the answers

    What is the primary source of nutrients for chondrocytes in hyaline articular cartilage?

    <p>Synovial fluid</p> Signup and view all the answers

    What maintains the radiolucent appearance of hyaline articular cartilage on X-ray?

    <p>Calcification</p> Signup and view all the answers

    Where do tendons and ligaments attach to bone in the body?

    <p>Entheses</p> Signup and view all the answers

    What causes bones to appear to be touching due to the loss of the spacer effect in arthritis?

    <p>Joint space narrowing</p> Signup and view all the answers

    What is the function of synovium in diarthrodial joints?

    <p>Nutrient supply to cartilage</p> Signup and view all the answers

    What happens to the reparative capacity of hyaline articular cartilage once it wears out?

    <p>It decreases significantly</p> Signup and view all the answers

    What are the two main components of articular cartilage?

    <p>(Correct) Type 2 collagen and proteoglycans</p> Signup and view all the answers

    How does hyaline articular cartilage obtain its nutrients?

    <p>(Correct) From synovial fluid and subchondral bone</p> Signup and view all the answers

    Why does hyaline articular cartilage look radiolucent on X-ray?

    <p>It is non-calcified.</p> Signup and view all the answers

    What is the main function of the type 2 collagen in hyaline articular cartilage?

    <p>Holding proteoglycans in check</p> Signup and view all the answers

    What is the primary role of chondrocytes in normal hyaline articular cartilage?

    <p>Maintaining the articular matrix</p> Signup and view all the answers

    What are the properties of hyaline articular cartilage?

    <p>Ability to withstand impact with tensile strength</p> Signup and view all the answers

    What is the reason behind the deformability of hyaline articular cartilage?

    <p>Proteoglycans' water-attracting properties</p> Signup and view all the answers

    In osteoarthritis (OA), which enzyme targets proteoglycans?

    <p>Aggrecanase</p> Signup and view all the answers

    'Synovial space' is a region where water is released by _____________ during loading of joints.

    <p>Proteoglycans</p> Signup and view all the answers

    'Regression to a more fetal type molecule' in osteoarthritis refers to a reversion to which chondroitin sulfate form?

    <p>&quot;Dermatan sulfate&quot;</p> Signup and view all the answers

    What stimulates cartilage metabolism and synthesis?

    <p>Matrix metalloproteases (MMPs)</p> Signup and view all the answers

    What inhibits the action of MMP enzymes in normal cartilage?

    <p>Type 2 collagen network breakdown</p> Signup and view all the answers

    Which enzymes are considered the 'villains' in the context of hyaline articular cartilage degradation?

    <p>Matrix metalloproteases (MMPs)</p> Signup and view all the answers

    What is the main target of stromelysin, also known as MMP 3?

    <p>Proteoglycans</p> Signup and view all the answers

    What upregulates the neutral matrix metalloproteases (NMMPs) according to the text?

    <p>IL-1 and plasmin</p> Signup and view all the answers

    In osteoarthritis, which enzyme targets the collagen arcade specifically?

    <p>Collagenase 13</p> Signup and view all the answers

    What inhibits and blocks the metalloprotease enzymes in normal hyaline articular cartilage?

    <p>TIMPs</p> Signup and view all the answers

    Which enzyme targets proteoglycans in the context of osteoarthritis?

    <p>MMP 3</p> Signup and view all the answers

    What is considered a characteristic of normal chondrocytes in hyaline articular cartilage?

    <ul> <li> <ul> <li>MMP enzyme activity</li> </ul> </li> </ul> Signup and view all the answers

    'Nasty' MMPs in osteoarthritis include which specific enzymes?

    <p>(P)MMP 1 and MMP 13</p> Signup and view all the answers

    What stimulates cartilage metabolism and synthesis according to the text?

    <p>Insulin-like growth factor and growth hormone</p> Signup and view all the answers

    Which enzyme is responsible for targeting PGs, or proteoglycans?

    <p>MMP 3</p> Signup and view all the answers

    What is the primary function of hyaline articular cartilage proteoglycans?

    <p>Protection from metallo proteases</p> Signup and view all the answers

    Where are the glycosaminoglycan (GAG) side chains attached in the proteoglycan monomers?

    <p>To the core protein</p> Signup and view all the answers

    Why are proteoglycan aggregates described as 'prisoners' in the collagen network?

    <p>To protect them from enzymatic degradation</p> Signup and view all the answers

    What is the main component responsible for attracting water into hyaline articular cartilage?

    <p>Glycosaminoglycans (GAGs)</p> Signup and view all the answers

    In which region of the proteoglycan core protein is keratan sulfate (KS) located?

    <p>Proximal or amino-terminal</p> Signup and view all the answers

    What effect do glycosaminoglycans (GAGs) being negatively charged have on hyaline articular cartilage?

    <p>Increases deformability</p> Signup and view all the answers

    'Regression to a more fetal type molecule' in osteoarthritis refers to a reversion to which form of chondroitin sulfate?

    <p>(C-4S) Chondroitin 4 sulfate</p> Signup and view all the answers

    What is the primary role of the hyaluronic acid binding region (HABR) in proteoglycan aggregates?

    <p>Binding to HA strands</p> Signup and view all the answers

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