Lecture 29

• What are the four primary tissue types?

  Epithelium, connective, muscle, nerve
• What are the main components of connective tissue?

  • Cells (permanent and transient)
  • Extracellular matrix (ECM)
  • Fibers (collagen, elastic)
  • Ground substance
• What is the function of connective tissue?

  Support, defense, protection, repair, nutrition
• What is the definition of connective tissue?

  An aggregation of loosely packed cells with ECM

  
• What are the classifications of connective tissue?

  Embryonic, connective tissue proper, specialized
• What are the types of embryonic connective tissue?

  1. Mesenchyme
  2. Mucous connective tissue
• What are the types of connective tissue proper?

  1. Loose connective tissue
  2. Dense connective tissue

  • Irregular
  • Regular

  
• What are the types of specialized connective tissue?

  1. Cartilage
  2. Bone
  3. Blood & hematopoietic tissue
  4. Adipose tissue (white and brown)
• What is parenchyma in connective tissue?

  Functional cellular units like epithelium
• What is the role of the stroma in connective tissue?

  Supporting structures within the tissue
• What is the basement membrane?

  A thin layer supporting epithelial cells
• What are the functions of ground substance in connective tissue?

  Glue, lubricant, barrier, tensile strength
• What are the components of the extracellular matrix (ECM)?

  • Fibers
  • Ground substance (GAGs, proteoglycans, glycoproteins)
  • Tissue fluid
• What are the types of fibers found in connective tissue?

  Collagen, elastic, reticular

  
• What is the most common cell type in connective tissue?

  Fibroblasts

  
• What is the role of fibroblasts in connective tissue?

  Synthesize extracellular fibers and ground substance

  
• What are myofibroblasts involved in?

  Wound healing
• What are macrophages derived from?

  Monocytes
• What is the function of macrophages?

  Phagocytosis and cytokine production
• What do mast cells secrete?

  Histamine, heparin, proteases
• What is metachromasia in mast cells?

  Granules stain a different color than dye

  
• What are the functions of the extracellular matrix (ECM)?

  1. Mechanical support
  2. Structural support
  3. Influence extracellular communication
  4. Tensile strength
  5. Regulate metabolic functions
• What is ground substance in connective tissue?

  Clear, viscous substance with high-water content
• What are glycosaminoglycans (GAGs)?

  Most abundant polysaccharide in ground substance
• What is the structure of proteoglycans?

  GAGs covalently attached to a core protein

  
• What are multi-adhesive glycoproteins (MAGs)?

  • Adhesive molecules
  • Stabilize ECM
  • Regulate cell movement and differentiation
• What is the most abundant glycoprotein in connective tissue?

  Fibronectin
• What is the function of collagen in connective tissue?

  Provides mechanical strength and support
• What type of collagen is the most abundant?

  Type I collagen
• What are the types of collagen fibers and their functions?

  • Type I: Mechanical strength (tendons, bones)
  • Type II: Resistance to pressure (cartilage)
  • Type III: Scaffolding for cells (reticular)
• What is the function of elastic fibers?

  Allows tissue to respond to stretch and recoil

  
• What unique amino acids are found in elastic fibers?

  Desmosine and isodesmosine

  
• What are reticular fibers and their functions?

  • Forms supporting framework for tissues
  • High affinity for silver nitrate stains
  • First collagen type synthesized during wound healing
• Where are reticular fibers commonly found?

  Bone marrow, lymph nodes, liver
• What is the role of reticular cells?

  Cover reticular fibers with cytoplasmic extensions