Articular Cartilage Structure Overview
27 Questions
26 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of interstitial fluid pressurization in joints?

  • To enhance the lubrication capacity of joint surfaces (correct)
  • To increase the friction coefficient during joint movement
  • To reduce load-bearing capacity of articular cartilage
  • To promote direct contact between bearing surfaces
  • Which lubrication method primarily uses a bearing surface created by a fluid film?

  • Mixed lubrication
  • Absorbed lubrication
  • Fluid-film lubrication (correct)
  • Boundary lubrication
  • What occurs during mixed lubrication in joint surfaces?

  • Fluid-film lubrication is completely absent
  • Both fluid-film and boundary lubrication coexist at different locations (correct)
  • Only fluid-film lubrication is present
  • Boundary lubrication is the sole mechanism
  • What happens to the friction coefficient when interstitial pressurization is high?

    <p>It becomes low</p> Signup and view all the answers

    Which type of wear involves direct contact between bearing surfaces without lubrication?

    <p>Interfacial wear</p> Signup and view all the answers

    What is the main consequence of prolonged immobilization of hyaline cartilage?

    <p>Degeneration of cartilage</p> Signup and view all the answers

    What is the primary purpose of articular cartilage?

    <p>To distribute joint loads and decrease stress at joints</p> Signup and view all the answers

    How does cyclic loading and unloading benefit cartilage?

    <p>Improves nutrient delivery to cartilage</p> Signup and view all the answers

    Which zone of articular cartilage contains the highest concentration of proteoglycans?

    <p>Middle Layer Radiate Stratum</p> Signup and view all the answers

    What occurs when cartilage is loaded in tension?

    <p>It breaks and tears</p> Signup and view all the answers

    Which of the following best describes the role of fluid flow in hyaline cartilage?

    <p>It is crucial for delivering nutrients</p> Signup and view all the answers

    What characterizes the Surface Tangent Layer of articular cartilage?

    <p>High collagen fibers oriented parallel to the joint surface</p> Signup and view all the answers

    What happens to proteoglycans during loading of the articular cartilage?

    <p>They become less saturated and more hydrophilic</p> Signup and view all the answers

    What is the main purpose of microfracture surgery on cartilage?

    <p>To stimulate blood flow and deliver nutrients</p> Signup and view all the answers

    What effect does rapid loading have on cartilage stiffness?

    <p>It increases collagen stiffness</p> Signup and view all the answers

    What effect does high compressive loading have on cartilage?

    <p>Prevents fluid flow and nutrition</p> Signup and view all the answers

    Which outcome is associated with loss of cartilage thickness?

    <p>Pressure point necrosis</p> Signup and view all the answers

    During unloading, which of the following occurs in articular cartilage?

    <p>Fluid flows back into the cartilage and permeability increases</p> Signup and view all the answers

    What characteristic of hyaline cartilage impedes its ability to repair itself?

    <p>Minimal blood supply</p> Signup and view all the answers

    What is the primary type of collagen found in articular cartilage?

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

    The radial orientation of collagen fibers in the Deep Layer of articular cartilage contributes mainly to:

    <p>Supporting the transition to underlying bone</p> Signup and view all the answers

    What is a characteristic feature of hydrophilic proteoglycans in articular cartilage?

    <p>They provide osmotic swelling pressure</p> Signup and view all the answers

    What determines the ability of the Surface Tangent Layer to decrease friction between joint surfaces?

    <p>The orientation of collagen fibers parallel to the joint surface</p> Signup and view all the answers

    What is primarily responsible for fatigue wear in bearing materials?

    <p>Continuous overuse without rest</p> Signup and view all the answers

    Which of the following effects can result from the disruption of the collagen-PG matrix in cartilage?

    <p>Increased frictional shear loading</p> Signup and view all the answers

    What factors relate to the progression of cartilage failure?

    <p>Magnitude of imposed stresses</p> Signup and view all the answers

    Which property is decreased as cartilage failure progresses?

    <p>Cartilage stiffness</p> Signup and view all the answers

    Study Notes

    Articular Cartilage

    • Articular cartilage is a thin layer covering the ends of bones where they meet to form joints.
    • It is primarily composed of water (70-85%), type II collagen (10-30%), and proteoglycans (8-10%).
    • The high water content makes it resilient and smooth.
    • Proteoglycans are essential for the cartilage's ability to absorb and distribute loads.
    • Collagen fibers provide tensile strength to the material.

    Structure and Zones

    • Articular cartilage is composed of four zones:
      • Zone I (Surface layer): The outermost layer oriented parallel to the joint surface, with high collagen content for load distribution and shear resistance. Low proteoglycan content.
      • Zone II (Transitional stratum): Contains randomly oriented collagen fibers, which permits deformations. Higher proteoglycan content compared to Zone I, and more water.
      • Zone III (Radiate stratum): Collagen fibers are oriented perpendicular to the surface with the highest proteoglycan content.
      • Zone IV (Calcified cartilage): The deepest layer, grading into the subchondral bone, with collagen fibers oriented vertically or radially to the joint surface. Tidemark is the boundary between Zone IV and the subchondral bone; it does not allow water to pass.

    Function

    • Distributes loads across the joints to reduce stress on bone.
    • Reduces friction between joint surfaces.
    • Supports smooth joint movement. Cartilage is smoother than glass on glass.
    • Proteoglycans (PGs) have negative charges, and resist expansion (due to water) by the tensile restraint provided by collagen.

    Cartilage Loading

    • Under compression, fluid flows out of the cartilage through pores in Zone I. This causes PGs to become less saturated and collagen to become compressed, making cartilage stiffer.
    • During unloading, fluid flows back into the cartilage.
    • Tensile stress on the cartilage leads to deformation and eventually break down, which is why excessive tensile loading can damage the cartilage. Cyclic loading and unloading are better for cartilage.

    Cartilage Injury and Repair

    • Cartilage injuries typically do not heal on their own due to lack of blood vessels and nerves.
    • Microfracture surgery can help by stimulating blood vessel growth into the area to bring nutrients to the injured site.
    • New cartilage is fragile and requires specific rehabilitation limitations (partial weight bearing for up to 5 weeks, running after at least 12 weeks).

    Cartilage Damage and Wear

    • Wear or damage (degeneration) occurs due to mechanical actions (e.g., overuse, impact loading).
    • Interfacial wear occurs when cartilage bears directly against cartilage without a fluid film.
    • Wear can weaken the collagen-proteoglycan matrix, and reduce a joint's load-bearing and lubricating abilities.
    • These changes can lead to increased permeability and decreased cartilage stiffness.
    • Increased magnitude and frequency of loading stresses worsens damage and wear.

    Cartilage Physiology

    • Hyaline cartilage lacks blood vessels and nerves; nourishment occurs through fluid flow during loading/unloading cycles.
    • Cartilage is designed to withstand compressive forces, but not tensile stress. Tensile stress is damaging.
    • Cartilage does not adapt readily to changes in stress, so poor loading can cause wear or damage.

    Immobilization

    • Prolonged immobilization can lead to cartilage degeneration.
    • Reduced motion results in reduced fluid flow and nutrition, leading to thinning, softening, or fissuring of the cartilage. Loss of cartilage thickness leads to pressure point necrosis.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Description

    This quiz covers the structure and composition of articular cartilage, including its importance in joint function. Explore the four distinct zones of cartilage and the roles of water, collagen, and proteoglycans in maintaining its properties. Test your understanding of the material and its implications in biomechanics.

    More Like This

    Joints and Articular Cartilage
    11 questions
    Anatomy of Synovial Joints
    5 questions

    Anatomy of Synovial Joints

    SnappyPiccoloTrumpet avatar
    SnappyPiccoloTrumpet
    joints/cartilage
    31 questions

    joints/cartilage

    ReasonableAqua5401 avatar
    ReasonableAqua5401
    Use Quizgecko on...
    Browser
    Browser