Podcast
Questions and Answers
What color does PAS staining produce when it reacts with carbohydrates?
What color does PAS staining produce when it reacts with carbohydrates?
What is the primary difference in magnification between light microscopes and electron microscopes?
What is the primary difference in magnification between light microscopes and electron microscopes?
Which statement correctly describes the resolution power of light microscopes?
Which statement correctly describes the resolution power of light microscopes?
What is the basis for the common staining methods utilized in histology?
What is the basis for the common staining methods utilized in histology?
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Which microscopy technique allows for three-dimensional visualization of a specimen's surface?
Which microscopy technique allows for three-dimensional visualization of a specimen's surface?
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What factor does NOT affect the magnification of a light microscope?
What factor does NOT affect the magnification of a light microscope?
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How is the resolution power of an electron microscope different from that of a light microscope?
How is the resolution power of an electron microscope different from that of a light microscope?
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What is the purpose of tissue fixation in microscopic procedures?
What is the purpose of tissue fixation in microscopic procedures?
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Which of the following types of cells are most effectively visualized using electron microscopy?
Which of the following types of cells are most effectively visualized using electron microscopy?
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What contributes to the higher resolution of electron microscopes over light microscopes?
What contributes to the higher resolution of electron microscopes over light microscopes?
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Study Notes
Introduction
- The presentation is about histology, specifically methods of staining tissue samples for microscopic analysis.
- The presenter is Dr. Dalia Eita.
- The institution is Mansoura National University.
Agenda
- Methods for preparing tissue samples for light microscopy
- Staining principles using Hematoxylin & Eosin
- Types of stains
- Types of microscopes
Learning Objectives
- Demonstrate tissue fixation and embedding procedures.
- Identify and explain common staining techniques.
- Explain the application of cytochemical and histochemical approaches.
- Compare light and electron microscopy.
Special Stains for Organic Components
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Carbohydrates:
- Periodic acid-Schiff (PAS) stain uses periodic acid to react with carbohydrates creating aldehyde groups, aldehyde group reacts with Schiff's reagent then turns magenta
- Best Carmine stain highlights glycogen, giving glycogen granules a red colour.
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Lipids:
- Frozen sections are used
- Sudan III stains lipids orange
- Sudan black stains lipids black
- Osmium tetroxide stains lipids black
Other Methods of Staining
- Vital stains: These stains are used to observe living cells e.g. staining of phagocytes (cells of the body's immune system) with Trypan blue or Indian ink.
- Metachromatic Stains: These stains show differences in color compared to that of the dye. An example is mast cell's granules which have a reddish-purple color when stained with toluidine blue.
- Enzyme Histochemistry: Frozen tissue sections are used to locate and study specific enzymes e.g alkaline phosphatase in kidney tubules.
Quiz (PAS stain)
- PAS stains carbohydrates and turns magenta.
Microscopy: Types of Microscopes
- Light microscopes: Used in educational settings, have magnifications of 40x, 100x, 400x, and 1000x.
- Electron microscopes: Higher magnification (up to 50,000x) and resolution allowing for observation of smaller structures compared to light microscope.
Resolution Power
- Resolution power measures the smallest distance between two particles that can be distinguished as separate particles.
- Light microscopes have a resolution power of about 0.2 micrometers (200 nanometers).
- Electron microscopes have a resolution power of around 1 nanometer.
Practical Class: How to Use a Microscope
- Step-by-step instructions on how to use a light microscope, are provided in the form of instructions in the presentation.
Micro Technique for Electron Microscopy
- Ultrathin sections (50-100 nm thick) are made using an ultramicrotome.
- Sections are stained using heavy metals (lead citrate and uranyl acetate)
- Dark components in electron micrographs are called electron-dense, while light components are called electron-lucent.
Scanning Electron Microscope (SEM)
- Allows for 3-dimensional visualization of the surface of a fixed specimen
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Description
Explore the fascinating world of histology with this quiz on tissue staining techniques. Learn about the various methods for preparing tissue samples, principles of staining using Hematoxylin & Eosin, and the differences between light and electron microscopy. Ideal for students and professionals in the field of biological sciences.
