Intro to Histo- Light Microscope

Question 1

What are 6 Pathological Diagnostic methods?

Answer 1

1. Needle biopsy
2. Endoscopic biopsy
3. Transvascular biopsy
4. Direct excision biopsy
5. Curettage biopsy endometrium
   * (when pt has heavy menstrual cycle)
6. Cytology

Question 2

What microscope do you use for Cells and Tissues?

Answer 2

Light Microscope

*Cells and tissues are colorless

• Must be stained

*Resolution and magnification are separate factors

Question 3

What microscope do you use for cytoplasmic structures?

Answer 3

Electron Microscope

Question 4

What is the Transmission Electron Microscope? (TEM)

Answer 4

1. High resolution to observe particles
2. Bean goes through specimen

Question 5

What is Scanning electron Microscope? (SEM)

Answer 5

1. High resolution for observing the surface of cells, tissues, and organs
2. Beam does not go through specimen

Question 6

What is the Fixation for Light Microscope?

Answer 6

1. Formalin

• Aqueous solution of formaldehyde (37% dilution)
• Inactivates degradative enzymes
• DOES NOT PERSERVE LIPIDS
  
  • Freezing perserves lipids
• Prevents
  
  • Autolysis
  • Postmorten degeneration
  • Bacterial growth
• Perserves tissue for dehydration

Question 7

What is CLEARING for Light Microscope?

Answer 7

1. Removal of alcohol
2. Increases refractive index
3. Embedded with paraffin wax
4. Uses

• Tolune
• (organic solvents: xylene, chloroform, benzene)

Question 8

What is Hematoxylin?

Answer 8

1. Used for Light Microscope staining
2. Basic dye (Cationic)

• Cl^-
• Positive charge on colored portion

3. Stains Acidic components
4. STAINS BLUE or PURPLE color
   * Heavily stained on Nucleus and cytoplasmic RNA
5. Used in Pancreatic acinar cells

Question 9

What is Metachromasia?

Answer 9

1. Tissue stains a different color than the dye itself

Ex: Stains purple instead of blue color of the dye

• Mast cell granules
• Cartilage
• Mucin
• Amyloid

Question 10

What is Eosin?

Answer 10

1. Used on Light Microscope
2. Acidic dye (Anionic)

• Na⁺
• Negative charge on colored portion

3. Acidophilic: Proteins (cytoplasmic or extracellular)
4. Stains Pink, Red, and Orange
5. Used in
   * Pancreatic acinar cells

*Nuclei not as clearly stained

Question 11

What can you view on a Light Microscope?

Answer 11

1. Thickness of hair
2. Cell
3. Bacterium

Question 12

What can you view on a Electron Microscope?

Answer 12

1. Atom
2. Small molecules
3. Macro-molecules
4. Virus

Question 13

What is the condenser on a Light Microscope?

Answer 13

1. Illuminates tissue by focusing and collecting a cone of light

Question 14

How to calculate total magnification on Light Microscope?

Answer 14

1. Multiply magnifying power of objective and eyepiece lense

Ex:

• Objective lense: 4X, 10X, 40X, 100X
• Eyepiece lense: 10X
  
  • 40x: Low magnification
  • 1000X: Highest magnification

Question 15

What is visible on Low magnification?

Answer 15

1. Finds orientation of slide
2. Organs

• Kidney
• Cortex
• Glomerulus
• Medulla

Question 16

What is visible on Medium Power Magnification?

Answer 16

1. Glomerulus
2. Proximal and distal convulated tubules
3. Nucleus
   * Dark purple spots

Question 17

What is visible on High Power Magnification?

Answer 17

1. Details of glomerulus
2. Cells of the parietal and visceral layer of Bowman’s capsule
3. Podocytes
4. Vascular and urinary pole
5. Cellular details