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30 Cards in this Set
- Front
- Back
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What are the four fundamental tissues?
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1. Epithelia
2. Connective tissue 3. Muscular tissue 4. Nervous tissue |
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Define resolution.
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The smallest distance between two particles at which they can be seen as separate objects
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What is maximal resolving power of light miscroscopes?
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about 0.2um
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What are the 6 types of microscopy discussed in class?
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1. Light Microscopy
2. Phase contrast and differential interference microscopy. 3. Polarized light microscopy 4. Confocal Microscopy 5. Fluorescence Microscopy 6. Electron Microscopy |
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What are the two lenses in light microscopy?
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Ocular (4X) and Objective
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How does light microscopy work?
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Light passes through specimen --> condenser collects and focuses light --> objective lens enlarges and projects it towards eyepiece --> Eyepiece magnifies image and projects it to retina
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What is phase contrast and differential interference microscopy used to see? How does it work?
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Unstained cells and tissues that are normally transparent;
Based on principle that light changes speed passing through cellular and ex cel structures with different REFRACTIVE INDICES. |
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What does Normarski Differential interference microscopy produce?
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3D images
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How does confocal microscopy work?
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Small spot of light from section crosses pinhole and reaches detector, rays from other planes are blocked by the blind. One very thin plane of the specimen is focuesd at a time. Expensive..wont use.
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How does polarized light microscopy work?
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Normal light passed through a polarizing filter..it exits filter vibrating in only one direction.Second filter placed above 1st with its main axis perp. No light passes through.
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How does fluorescence microscopy work? Excites with UV light in what range?
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Substances that when irradiated with light of a spec. wavelength emits light with a longer wavelength.;
Visible Range |
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Fluorescence microscopy is often combined with which other type of microscopy?
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Confocal
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How does electron microscopy work? What resolution? What do you see?
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Electrons deflected by electromagnetic fields. Some electrons interact with atoms in specimen and change course. Images detected by charged coupled devices;
High resolution..0.1nm; Very thin specimens. |
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What are three steps to tissue preparation?
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1. Fixation
2. Embedding 3. Staining |
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What does FIXATION do?
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Stops degradation (prevents autolysis and preserves strucure.). Needs to be quick to be effective.
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What is fixation necessary for?
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Making permanent sections.
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What are the two types of fixation? Which is more commonly used?
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Chemical and physical methods.;
Chemical |
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How does chemical fixation work?
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Tissues immersed in stabilizing or cross-linking agents called FIXATIVES.
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What are the common fixatives used in chemical fixation? What is the added step for electron microscopy?
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formaldehyde and glutaraldehyde. They react with amine group on proteins.;
Osmium tetroxide. |
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What ids embedding? What materials are used? What are the two embedding steps?
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Tissue embedded in a solid medium to facilitate sectioning into thin sections using a microtome.;
Paraffin and plastic resins used.; 1. Dehydration 2. Clearing |
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How is tissue dehydrated and cleard?
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With a successive graded series of washes in ethanol/water. Ethanol is then replaced by solvent compatible with the embedding material (Xylene for paraffin). When solvent permeates tissue it CLEARS. Then tissue placed in melted embedding medium and heated to evaporate solvent. Hard blocks then sectioned by microtome.
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How is staining done?
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Dyes stain components more or less selectively. Most dyes act as acids or bases.
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If you are a basophilic tissue are you acidic or basic?
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Acidic (base loving)
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If you are an acidophilic tissue are you acidic or basic?
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Basic (acid loving)
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What are some basic dyes? Do they stain acids or bases?
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Toluidine blue, methylene blue, haematoxylin;
Acids...nucleic acid, GAGs |
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What are some acidic dyes? Do they stain acids or bases?
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Orange G, acid fuchsin, eosin.;
Bases (acidophilic compounds)...like mitochondria, secretory granules, and collagen. |
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What are the most commonly used dyes?
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Haematoxyline and Eosin (H & E);
Hae stains cell nucleus and other acidic things blue. Eosin stains cytoplasm and collagen pink |
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How does Periodic-Schiff (PAS) reaction work?
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Stains polysaccharides based on transformation of glycol groups into aldehyde residues.
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How can you stain lipids?
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Requires lipid soluble dyes like Sudan black, oil red O
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Goblet cells have high concentration of what?
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Polysaccharides. So PAS used to stain them.
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