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

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

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

Which enzyme targets the type 2 collagen arcade?

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

In osteoarthritis (OA), which enzyme targets proteoglycans?

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

What upregulates MMP enzymes in osteoarthritis?

<p>Plasmin (D)</p> Signup and view all the answers

Which enzyme targets collagen and is considered a collagenase?

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

What inhibits the action of MMP enzymes in normal cartilage?

<p>TIMPS (A)</p> Signup and view all the answers

What stimulates cartilage metabolism and synthesis?

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

What is the main function of proteoglycans in cartilage?

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

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

<p>Core protein (A)</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 (D)</p> Signup and view all the answers

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

<p>Distal carboxyl end (A)</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 (D)</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 (B)</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 (A)</p> Signup and view all the answers

Which type of GAG chain is enriched in glucosamine?

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

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

<p>They undergo mitoses in brood capsules (B)</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) (D)</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 (A)</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 (D)</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 (B)</p> Signup and view all the answers

How do proteoglycans in hyaline articular cartilage attract water?

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

What is the main structural component of hyaline articular cartilage?

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

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

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

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

<p>Calcification (C)</p> Signup and view all the answers

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

<p>Entheses (A)</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 (A)</p> Signup and view all the answers

What is the function of synovium in diarthrodial joints?

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

What are the two main components of articular cartilage?

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

How does hyaline articular cartilage obtain its nutrients?

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

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

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

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

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

What are the properties of hyaline articular cartilage?

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

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

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

In osteoarthritis (OA), which enzyme targets proteoglycans?

<p>Aggrecanase (B)</p> Signup and view all the answers

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

<p>Proteoglycans (D)</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; (C)</p> Signup and view all the answers

What stimulates cartilage metabolism and synthesis?

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

What inhibits the action of MMP enzymes in normal cartilage?

<p>Type 2 collagen network breakdown (C)</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) (D)</p> Signup and view all the answers

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

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

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

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

In osteoarthritis, which enzyme targets the collagen arcade specifically?

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

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

<p>TIMPs (C)</p> Signup and view all the answers

Which enzyme targets proteoglycans in the context of osteoarthritis?

<p>MMP 3 (C)</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 (A)</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 (D)</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 (C)</p> Signup and view all the answers

Which enzyme is responsible for targeting PGs, or proteoglycans?

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

What is the primary function of hyaline articular cartilage proteoglycans?

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

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

<p>To the core protein (B)</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 (A)</p> Signup and view all the answers

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

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

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

<p>Increases deformability (B)</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 (C)</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 (A)</p> Signup and view all the answers

Flashcards

Type 2 Collage in Cartilage

Main structural protein providing tensile strength.

Synovium Role

Lines joint, secretes synovial fluid for lubrication and nutrients.

Cartilage Radiolucency

Because cartilage is non-calcified.

Cartilage Loss Effect

Causes bone on bone contact.

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Cartilage Nutrient Source

Synovial fluid and subchondral bone.

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MMP 1 Target

Enzyme that degrades collagen.

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MMP 3 Target

Enzyme that attacks proteoglycans.

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Plasmin's Role in OA

Increases MMP enzyme activity.

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MMP 13 Action

Breaks down collagen.

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TIMPS Role

Tissue Inhibitors of Metalloproteinases, prevents cartilage degradation.

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IGF Effect

Promotes cartilage growth.

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Proteoglycans Function

Maintain cartilage hydration.

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Core Protein Role

Determines GAG addition sites.

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Water Content in Cartilage

Fluctuates with joint loading/unloading.

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CS Location

Located at the distal carboxyl end.

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GAGs Negative Charge

Attracts/absorbs water, increases deformability.

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Aggrecan Role

Maintain water content and prevent enzymatic degradation.

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Proteoglycan 'Prisoners'

Large size/hydrophilicity traps them.

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Glucosamine Enriched GAG

'Keratan' sulfates (KGS).

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Fetal Type Molecule

'Chondroitin 4 sulfate (C-4S)'

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Water Source during Loading

Proteoglycans (PGs).

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Type 2 Collagen's Function

Giving the cartilage its tensile strength

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Proteoglycans (PGs) Role

Attracting water into the cartilage

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Chondrocytes in Osteoarthritis

They undergo mitoses in brood capsules

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Deformability of Cartilage

Proteoglycans with negatively charged GAGs

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Broken Collagen Effects

Aggregates escape into the synovial space

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Hook Region Purpose

Attach multiple subunits to hyaluronic acid.

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Structural Cartilage Component

Type 2 collagen.

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Cartilage Nutrient Source

Cartilage obtains its nutrients from fluid and bone.

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Touching Bones Cause

Joint space narrowing

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