Intro to Histology

• Study of tissue of the body and how these tissues are arranged to constitute organs?

  Histology
• Greek root histo can be translated as either?

  tissue or web
• Best example of tissue is?

  blood
• TWO INTERACTING COMPONENTS OF TISSUE?

  Cells and extracellular matrix
• ECM of blood?

  plasma
• Consists of many kinds of macromolecules, most of which form complex structures, such as collagen fibrils and basement membranes?

  Extracellular Matrix (ECM)
• it is where cells are suspended? Extracellular Matrix (ECM)
• It produce the ECM and are also influenced and sometimes controlled by matrix molecules?

  Cells
• it is the living component of tissue?

  cells
• Microscopy


  Technical field of microscopes to view samples & objects that cannot be seen with the unaided eye
• Anton van Leeuwenhoek


  The father of microscopy
• Microscopy

  "Mikros" and "skopein" which means "small" and "to look"
• Microscope


  Instrument that magnifies an image and allows visualization of greater detail than is possible with the unaided eye
• Microscope


  • Design to make fine details visible
• Tasks a microscope must accomplish

  1. Magnification

  2. Resolution

  3. Contrast
• Magnification


  Magnifies the image of the specimen
• Resolution

  • Separate the details in the image
  • Must be able to see distinctively
• Contrast

  Overall visibility
• Bright-field microscope


  The most commonly used microscope in the laboratory wherein the specimen is observed using visible light and two sources of magnification are used
• Bright-field microscope

  • Stained tissue is examined with ordinary light passing through the preparation
• Bright-field microscope is essentially consist of?

  1. Light source

  2. Condenser

  3. Stage

  4. Objective lens

  5. Ocular
• PARTS OF THE MICROSCOPE?

  Base, arm, stage, substage, mechanical stage, eyepiece or ocular lens, and objective
• Focus knobs

  • Used to adjust the focus of the microscope
• Types of focus knobs

  • Coarse adjustment knob
  • Fine adjustment knob
• Coarse adjustment knob


  • Used to move the stage up and down to bring the specimen into rough focus
  • Alters distance rapidly and is used to bring the specimen into the field of view using an objective having low magnification power
• Fine adjustment knob


  • Used for finer focusing
  • Changes the distance very slowly and permits better viewing of the object
  • One revolution of the fine focusing knob should generally move the mechanical stage by 100 um
• Scanner – shortest – 4x

  Low power objective (LPO) – 10x

  High power objective – 40x

  Oil immersion – 100x
• microscope that is most useful for biological studies?

  ATOMIC FORCE MICROSCOPE
• One of the most powerful tools for studying the surface topography at molecular and atomic resolution?

  ATOMIC FORCE MICROSCOPE
• Digital procedure that is an alternative to the examination of glass slides using a light microscope?

  VIRTUAL MICROSCOPY
• Phase contrast microscopy

  • Uses a lens system that produces visible images from transparent objects
  • Can be used with living, cultured cells
• Principle of phase contrast microscopy

  Light changes its speed when passing through cellular and extracellular structures with different refractive indices
• Applications of phase contrast microscopy

  • Used to examine living cells and tissues
  • Used extensively to examine unstained semithin (approximately 0.5 um) sections of plastic-embedded tissue
• 2 modifications of PHASE CONTRAST MICROSCOPY:

  Interference microscope and Differential interference microscope
• Dark field microscopy

  • Only light that has scattered or diffracted by structures in the specimen reaches the objective
• Uses of dark field microscopy

  • Examining urine for crystals (uric acid and oxalate)
  • Demonstrating specific bacteria such as spirochetes
• Dark field microscopy


  Equipped with a special condenser that illuminates the specimen with strong, oblique light
• Useful in examining urine for crystals (uric acid and oxalate), and in demonstrating specific bacteria such as spirochetes?

  DARK FIELD MICROSCOPY
• Produces and focuses a very narrow beam of electrons?

  Electron microscope
• Electron microscope


  Microscope that uses a beam of electron (instead of a beam of light) and electromagnets (instead of glass lenses)