Chapter 1

• microscopy


  magnifies and makes objects clearer
• histology

  study of tissues
• four types of tissues

  epithelial, connective, nervous, muscle
• light microscope


  magnification: 1500

  resolution: 0.1 micro

  thickness: 1 micro
• electron microscope


  magnification: 200,000

  resolution: 0.1 nm

  thickness: <0.1 micron
• fixation

  with formaldehyde/formalin glutaraldehyde
• dehydration


  multiple rounds with increasing ethanol concentration
• clearing


  with organic solvent (i.e. xylene)
• embedding

  1. paraffin wax (general)
  2. resin/plastic (thin)
  3. glycerol (fats + active enzymes + frozen sectioning)
• sectioning

  microtome (thin) & ultratome (super thin)
• Hematoxylin Stain


  basic stain: stains acidic molecules

  blue/purple/black
• Eosin stain


  acidic stain: stains basic molecules

  pink/orange
• Silver impregnation stain


  stains goblet cells
• Orcein stain


  stains elastic fibers
• Azure A stain


  stains mast cells
• Sudan Black B stain


  stains fat cells
• Alkaline phosphatase stain 


  stains goblet cells
• Tissue smear 


  specimen spread thinly on slide
• Tissue whole mount 


  not sectioned
• Teased tissue 


  tissue picked apart with a needle
• Cross section 


  one hollow circle
• Oblique section


  diagonal sectioning
• Longitudinal section 


  two thin sections
• Longitudinal tangential section 


  one thick section
• Tangential section 


  two connected holes
• Osmium 


  can use for fixation and staining
• Vita stain


  staining live cells: done with blood smear