Lab 1 - Tissue Structure and Fetal Pig Digestive Anatomy
   

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Tissue Types

Four Basic Tissue Types

  • Epithelial (e.g., skin)
  • Connective
  • Muscle
  • Nervous
Epithelial Tissue
Epithelia face either internal spaces or the outside world (note that the lumen of your intestines is actually the outside world).
Epithelial tissues are classified by:
Number of cell layers
  • Simple (1 cell layer)
  • Stratified (>1 cell layer)
    • Shape of cells
  • Squamous (flat, ëscalyí cells)
  • Cuboidal (ësquareí cells)
  • Columnar (tall cells)
    		•       
    Click here for diagrams and micrographs of epithelia
         
    Example Epithelium: The Integument
    Two layers
    • Epidermis
    • Dermis
    Functions
  • protection - physical and biological insults
  • exchange area
  • thermoregulation
  • sensory reception
  • communication
    		•         
    Simple Epithelia
  • Simple: 1 layer of cells
  • Examples: lungs, intestines, glands
  • Good for: absorbtion or release of materials or heat
    		•

    Stratified Epithelia

    • Examples: skin, stomach
    • Good for: Areas subject to ‘wear and tear’
      • Skin: physical abrasion
      • Stomach: chemical and enzymatic damage

    Connective Tissue

    • Fibers in an acellular ground substance
      • Ground substance may be liquid, gelatinous or solid
    • Functions
      • Protection
      • Support
      • Fat and Mineral storage
      • Blood formation

    Bone

    • Compact bone is constructed primarily of Haversian Systems, layers of material in which osteocytes are encased. Osteocytes occupy lacunae and make cytoplasmic connections to each other via canaliculi
    		  
    Click here for pictures of bone structure
           

    Cartilage and Loose Connective Tissue

    • Example: Loose connective tissue in a joint - cells in liquid ground substance
    • Example Two: Hyaline cartilage - cells in gelatinous, firm ground substance
    Click here for cartilage pictures
           

    Muscle Tissue

    Three Basic Types defined by:

    • Location
      • Skeletal: generally attached to and moves the skeleton
      • Smooth: internal organs, blood vessels, skin
      • Cardiac: heart
    • Microscopic appearance
      • smooth (smooth)
      • striated (skeletal, cardiac)
    • Control
      • Voluntary (skeletal)
      • Involuntary (smooth, cardiac)
    		      
     
    Click here for pictures of muscle tissue
         

    Nervous Tissue

    Two basic cell types

    • Neurons - functional unit of nervous system
      • Variety of shapes

       

    • Glia (‘glue’)
      • Different types with variety of shapes
      • Variety of functions including support and improving conduction in neurons
    		      
    Neurons in hippocampus  
                   
             
              Myelin stain in human brain (myelin is a product of glial cells that enhances nerve action potential conduction)
                             
      Micrograph of astrocyte        
         
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