Histo Lecture 6

  1. Connective Tissue Functions
    • -Provide and maintain form in the body
    • -Provide a matrix that connects and binds cells and tissues together
    • -Serve as a reservoir for hormones controlling cell growth and differentiation
    • -Medium through which nutrients and metabolic wastes are exchanged between cells and their blood supply
  2. All CT consists of three main components:
    • -Cells
    • -Fibers (protein polymers)
    • -Ground substance
  3. What type of cells exist in connective tissue?
    Many different cell types among various tissues
  4. What type of fibers exist in CT?
    Predominately collagen fibers, also reticular and elastic fibers
  5. What type of ground substance exists in CT?
    Viscous mixture of water, proteoglycans, glycoasminoglycans, and glycoproteins (laminin, fibronectin)

    -Ground substance and fibers = extracellular matrix (ECM)
  6. Types of mesenchymal cells:
    -Fibroblasts, chondrocytes, osteoblasts, adipocytes, endothelial cells, smooth muscle cells
  7. Types of hematopoietic cells:
    -Mast cells, basophils, eosinophils, neutrophils, macrophages, lymphocytes (T&B cells), red blood cells (RBC)
  8. Types of Macrophage-like cells:
    Monocytes (blood), macrophage (tissue), multinuclear giant cell (CT), Kupffer cell (liver), microglia (CNS), Langerhans cell (skin), dendritic cell (lymph nodes), oseoclast (bone)
  9. Name important CTs:
    Tendons, ligaments, aponeuroses, dermis, organ capsules, stroma of organs, covering of muscles and nerves and membranes (meninges) surrounding CNS
  10. Facts about Collagen Fiber
    • -Polymer of collagen protein molecules, typically arranged in fiber bundles
    • -Each monomer collagen fiber is made of bundled collagen fibrils
    • -More than 25 "collagen types"; types I, II, III, and IV are most abundant
    • -Collagen provides resistance to tensile forces
  11. Describe Type I collagen
    Strongest, largest collagen fibers; most abundant collagen type
  12. Describe Type II collagen
    Found in articular cartilage and fibrocartilage
  13. Describe Type III collagen
    Synonymous with reticular fibers; found in skin, artery wall, scar tissue
  14. Describe Type IV collagen
    Major filament of basement membranes (basal lamina)
  15. Describe Reticular Fibers
    • -Composed of type III collagen fibrils
    • -Small diameter and "loosely" arranged (flexible network for organs)
    • -Abundant in smooth muscle, endoneurium (neurons), and framework for hemtopoietic organs
    • -Also located in papillary layer of the dermis
  16. 3 Types of Elastic fibers
    • -Oxytalan
    • -Elaunin
    • -Elastin
  17. Describe Oxytalan
    Small fibers that do not actually contain elastin protein but are resistant to tensile forces
  18. Describe Elaunin
    Mixture of elastin protein and oxytalan fibers
  19. Describe Elastin
    Polymers of elastin aggregate in the center of elastic fibers and are surrounded by network of oxytalan and elaunin fibers
  20. Describe Ground substance (tissue fluid)
    Viscous, hydrophilic substance with many macromolecules; occurs "between" cells
  21. Describe Macromolecules and give some examples
    • -Glycoasminoglycans, proteoglycans, glycoproteins
    • -Bind cell surface receptors to fiber components of ECM
    • -Ancher cells within ECM; provides tissue strength and rigidity
    • (ECM = fibers + ground substance)
  22. Types of Glycoasminoglycans and where they are found
    • Keratan Sulfate = cartilage, nucleus pulposus, annulus fibrosus
    • Hyaluronic acid - articular cartilage
    • Chondroitin 4-sulfate = cartilage, bone, skin
    • Chondroitin 6-sulfate = cartilage, skin, aorta
    • Dermatan sulfate = skin, tendons
    • Heparan sulfate = lung, liver, basement membrane
  23. Types of CT proper
    • -Loose CT
    • -Dense CT (regular or irregular)
  24. Types of Specialized CT
    Adipose, elastic, hematopoietic (blood), and mucous tissue (umbilical cord)
  25. Types of supporting CT
    Cartilage and bone
  26. Functions of Loose CT
    • -Supports structures that are normally uner low pressure and low frictions forces
    • -Flexible tissue, well vascularized, not very resistant to tensile stress
    • -Contains mainly fibroblasts and collagen, with lesser amounts of elastic and reticular fibers
    • -Very common; found in many tissues (epithelium, dermins, blood vessels, lining cavities)
  27. Functions of Dense CT
    • -Main function is to offer resistance to tensile force and protection of tissues
    • -Fewer cells (fibroblasts) and predominance of collagen fibers compared to loose CT
    • -Minimally flexible and highly resistant to stress (especially tension)
    • -composed of irregular and regular types, depending on arrangement of collagen fibers of the ECM
  28. Description of Dense Regular CT
    • -Collagen bundles arranged into a definitive, linear pattern
    • -Linear orientation of fibers (and fibroblasts) is designed to withstand prolong stresses exerted in the direction of fiber alignment
    • -Ex. - tendons, ligaments
  29. Description of Dense Irregular CT
    • -Collagen fibers are arranged in bundles without a definite orientation
    • -Provide resistance to stress in all directions
    • -Ex. - Dermis
  30. Description of Elastic Tissue
    • -Composed of thick, parallel elastic fiber bundles, and fibroblasts
    • -Thin collagen fibers are scattered among the elastic fiber bundles
    • -Abundant elastic content confers yellow color
    • -tissue is designed to provide elasticity to tissues; found mainly in ligaments of vertebral column (ligamentum flavum)
  31. Description of Reticular Tissue
    • -Specialized loose connective tissue
    • -Provides architectural framework for bone marrow, lymph nodes, spleen, and liver
    • -Matrix of intertwined, branched network of reticular fibers secreted by reticular cells (specialized fibroblasts that produce reticular fibers)
    • -Reticular fibers and cells form a sponge-like structure where ells and fluids can move easily
Card Set
Histo Lecture 6
Intro to Connective Tissue