Podcast
Questions and Answers
What is the resolution power of an electron microscope?
What is the resolution power of an electron microscope?
- 10 nm
- 1 micron
- 0.2 micron
- 0.2 nm (correct)
Which stain is most suitable for visualizing lipids?
Which stain is most suitable for visualizing lipids?
- Hematoxylin and eosin stain
- Sudan stain (correct)
- Masson's trichrome stain
- Silver impregnation
What is the primary purpose of fixation in fresh tissue?
What is the primary purpose of fixation in fresh tissue?
- Prevent putrefaction and autolysis (correct)
- Clear the sections
- Remove water
- Replace alcohol
Which of the following statements about Hematoxylin is accurate?
Which of the following statements about Hematoxylin is accurate?
What is the definition of vital stain?
What is the definition of vital stain?
What is the standard contrasting technique used in transmission electron microscopy?
What is the standard contrasting technique used in transmission electron microscopy?
What color does glycogen stain using Best's carmine stain?
What color does glycogen stain using Best's carmine stain?
Which method is used to detect ATPase enzyme in muscle fibers?
Which method is used to detect ATPase enzyme in muscle fibers?
What type of microscope utilizes fluorescent light?
What type of microscope utilizes fluorescent light?
What is the principle behind immunohistochemistry?
What is the principle behind immunohistochemistry?
In histochemistry, what color is observed when detecting nucleic acids using the Feulgen reaction?
In histochemistry, what color is observed when detecting nucleic acids using the Feulgen reaction?
Which staining method is used to visualize lipids in tissue?
Which staining method is used to visualize lipids in tissue?
What type of fixation method is used in electron microscopy to preserve ultrastructural details?
What type of fixation method is used in electron microscopy to preserve ultrastructural details?
What is the primary purpose of eosin in histological staining?
What is the primary purpose of eosin in histological staining?
Which of the following statements about neutral stains is correct?
Which of the following statements about neutral stains is correct?
Which statement accurately describes vital staining?
Which statement accurately describes vital staining?
What color does Masson’s stain give to collagen?
What color does Masson’s stain give to collagen?
What phenomenon results in a metachromatic stain?
What phenomenon results in a metachromatic stain?
Which of the following dyes is commonly used in supravital staining?
Which of the following dyes is commonly used in supravital staining?
How do supravital stains primarily differ from vital stains?
How do supravital stains primarily differ from vital stains?
Which type of stain is known to stain specific cell components with a color change?
Which type of stain is known to stain specific cell components with a color change?
What is the purpose of deparaffinization in the paraffin technique?
What is the purpose of deparaffinization in the paraffin technique?
Which staining technique is primarily used for observing nuclear structures?
Which staining technique is primarily used for observing nuclear structures?
What is the correct order of steps involved in staining paraffin sections?
What is the correct order of steps involved in staining paraffin sections?
What charge do acidic stains carry, and what do they typically stain?
What charge do acidic stains carry, and what do they typically stain?
During the hydration step, which sequence of alcohol concentrations is used?
During the hydration step, which sequence of alcohol concentrations is used?
What is the final step following the staining process?
What is the final step following the staining process?
What is the role of eosin in the staining process?
What is the role of eosin in the staining process?
Which of the following best describes a basic stain?
Which of the following best describes a basic stain?
Study Notes
Light and Electron Microscopy
- Light Microscope (LM)
- Uses visible light for illumination
- Uses glass condensers and lenses for focusing
- Resolution: 0.2 micrometers, Magnification: up to 4,000x
- Produces colored images
- Electron Microscope (EM)
- Two Types: Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM)
- Uses a beam of electrons for illumination
- Uses electromagnetic lenses for focusing
- Resolution: 0.2 nanometers, Magnification: up to 400,000x
- Produces black and white images
Staining Techniques
-
Hematoxylin and Eosin (H&E) Stain
- Most common stain used in histological techniques
- Hematoxylin: stains nuclei blue (basophilic)
- Eosin: stains cytoplasm pink (acidophilic)
-
Basic vs Acidic vs Neutral Stains
- Basic Stains: carry a positive charge (e.g., Hematoxylin, Methylene blue)
- Acidic Stains: carry a negative charge (e.g., Eosin)
- Neutral Stains: combination of acidic and basic dyes, stain all tissue components
-
Vital vs Supravital Stains
- Vital Stains: stain living cells within a living animal (in vivo)
- Supravital Stains: stain living cells outside the body (in vitro)
-
Trichrome Stains
- Use three different dyes to differentiate tissue components (e.g., Masson's stain)
- Differentiate collagen from muscle
- Masson's Stain: stains collagen green, nuclei blue, and muscle red
-
Metachromatic Stains
- Stain certain cell components with a color different from the dye used
- The phenomenon is called metachromasia
- Example: Toluidine blue staining of mucopolysaccharide granules in mast cells changes to violet
Histochemical and Immunohistochemical Stains
-
Histochemistry
- Localizes substances in tissue based on chemical reactions between cell components and stains
- Reaction produces a permanent colored precipitate
- Applications: detecting nucleic acids, enzymes, glycogen, and lipids
-
Immunohistochemistry
- Combines morphology and biochemistry to identify specific antigens
- Based on antibody-antigen reactions
- Visualizes the site of reaction microscopically
Paraffin Technique (Routine Histological Section)
- Steps:
- Selection and obtaining tissue
- Fixation
- Washing
- Dehydration
- Clearing
- Infiltration and Embedding
- Microtomy and Sectioning
- Mounting
- Deparaffinization
- Hydration
- Staining
- Dehydration
- Clearing
- Mounting
- Cleaning and labeling
Transmission Electron Microscopy (TEM)
- Most common stain used for ultrathin sections
- Heavy metals are used for staining
- Double contrast method with uranyl acetate (UA) and lead citrate is standard technique
- Original TEM images are in grayscale
Types of Microscopes
- Light Microscopes:
- Conventional light microscope
- Polarizing microscope
- Phase contrast microscope
- Dark-field microscope
- Other Microscopes:
- Fluorescent microscope
- X-ray microscope
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Description
This quiz covers the fundamental concepts of light and electron microscopy, highlighting their differences, magnification, resolution, and image production. It also discusses various staining techniques used in histology, including Hematoxylin and Eosin staining. Test your understanding of microscopy principles and techniques!
