HISTOLOGY - MODULE 4

• Cartilage


  is a tough, durable form of supporting connective tissue, characterized by an extracellular matrix (ECM) with high concentrations of GAGs and proteoglycans, interacting with collagen and elastic fibers
• chondrocytes


  The primary cell that makes cartilage is
• lacunae


  chondrocyte synthesize and maintain all ECM components which resides within the matrix cavity called
• •type II collagen fibrils, hyaluronan, and the sulfated GAGs on densely packed proteoglycans


  The physical properties of cartilage depend on electrostatic bonds between
• diffusion from capillaries in surrounding connective tissue (the perichondrium)

  chondrocytes receive nutrients by
• yes lods


  is cartilage avascular?
• perichondrium


  is a sheath of dense connective tissue that surrounds cartilage in most places, forming an interface between the cartilage and the tissues supported by the cartilage
• hyaline and elastic cartilage

  perichondrium can be seen in the __
• fibrocartilage, articular cartilage, and epiphyses

  perichondrium can't be seen in the __
• articular cartilage


  covers the ends of bones in movable joints and which erodes in the course of arthritic degeneration, lacks perichondrium and is sustained by the diffusion of oxygen and nutrients from the synovial fluid.
• Resilience


  is the capacity of bone to elastically store energy and thus resist microdamage
• HYALINE CARTILAGE


  •The most common of the three types
• HYALINE CARTILAGE

  •Homogeneous and semitransparent in the fresh state
• because of its small and evenly dispersed collagen fibers

  why does the matrix of the hyaline cartilage appears transparent?
• lacunae

  chondrocytes are found in the spaces or ___
• 40% type II collage


  what type of collagen can seen in hyaline cartilage and its percentage
• aggrecan


  most abundant proteoglycans in hyalin cartilage and it make the matrix generally basophilic
• chondronectin


  proteins binds specifically to GAGs, collagen, and integrins, mediating the adherence of chondrocytes to the ECM
• territorial matrix

  •near the chondrocytes

  •relatively richer in GAGs than collagen

  •stain intensely basophilic
• interritorial matrix

  •away from the chondorcytes

  •richer in collagen

  •less basophilic
• chondrocytes and chondroblasts

  major cells of hyaline cartilage
• chondroblasts


  •have an elliptic shape or round and may appear in groups of up to eight cells (isogenous aggregates)
• chondrocytes


  Active in secreting Collagens and other ECM component (sulfated GAGs and proteoglycans
• somatotrophins


  ‒promotes the release of somatomedins, which directly stimulate the cells of hyaline cartilage.
• elastic cartilage


  •similar to hyaline cartilage except that it contains an abundant network of elastic fibers in addition to a meshwork of collagen type II fibrils
• fibrocartilage


  •Essentially a mixture of hyaline cartilage and dense connective tissue.
• yes na yes because of the scarcity of proteoglycans

  is fibrocartilage acidophillic? why?
• mesenchyme


  is the precursor for all types of cartilage.
• chondroblasts


  Mitosis and initial cell differentiation produces a tissue with condensations of rounded cells called
• interstitial (endogenous) and appositional (exogenous) growth

  2 types of cartilage growth
• interstitial growth (endogenous)


  •Type of cartilage growth that expands the cartilage from within and growth in length of long bones

  •Possible only to young cartilage

  •mitotic division of preexisting chondrocytes
• •Type of growth which is the function of the perichondrium

  •chondroblast differentiation from progenitor cells in the perichondrium
• Bone


  is a specialized connective tissue composed of calcified extracellular material
• osteoblasts, osteocytes, osteoclasts

  3 major cell types of bones
• osteoblasts

  Are bone forming cells, for remodeling & repair
• osteocalcin and matrix vesicles

  Osteoblasts release:

  _______ which binds Ca ions and ______ which is rich in alkaline phosphatase and other enzymes and raises the PO4 ions
• osteoid


  Matrix components are secreted at the cell surface in contact with existing bone matrix, producing a layer of unique collagen-rich material called
• osteocyte


  •Most abundant cells in bone

  •Produce the components needed to maintain the calcified matrix and their death is followed by rapid matrix resorption
• osteocyte


  mature bone cell that maintains the bone matrix
• gap junction

  Osteocytes communicate with other cells via what type of junction?