Podcast
Questions and Answers
What type of group is added to a dye to alter its color?
What type of group is added to a dye to alter its color?
What is the main function of an Auxochrome?
What is the main function of an Auxochrome?
At what pH range do both dyes and tissues ionize?
At what pH range do both dyes and tissues ionize?
What type of tissue components are acidic due to phosphoryl groups?
What type of tissue components are acidic due to phosphoryl groups?
Signup and view all the answers
What is the property of solid objects that allows them to attract and hold other substances on their free surfaces?
What is the property of solid objects that allows them to attract and hold other substances on their free surfaces?
Signup and view all the answers
What is the term for the amount of time it takes for a tissue to stain?
What is the term for the amount of time it takes for a tissue to stain?
Signup and view all the answers
What type of staining technique involves over-staining and then de-staining a tissue?
What type of staining technique involves over-staining and then de-staining a tissue?
Signup and view all the answers
What is the term for the type of staining that achieves satisfactory differential coloration of the tissue without differentiation?
What is the term for the type of staining that achieves satisfactory differential coloration of the tissue without differentiation?
Signup and view all the answers
Why are tissues transparent and colorless when examined with a light microscope?
Why are tissues transparent and colorless when examined with a light microscope?
Signup and view all the answers
What is the purpose of histological techniques in tissue examination?
What is the purpose of histological techniques in tissue examination?
Signup and view all the answers
What is the reason behind the coloration of tissues when stained with a dye?
What is the reason behind the coloration of tissues when stained with a dye?
Signup and view all the answers
What is the ability of a stain to demonstrate a tissue substance in low concentration?
What is the ability of a stain to demonstrate a tissue substance in low concentration?
Signup and view all the answers
What is vital staining used for?
What is vital staining used for?
Signup and view all the answers
What is the basis of elective solubility in staining?
What is the basis of elective solubility in staining?
Signup and view all the answers
What is the reason why the nucleus is not stained in vital staining?
What is the reason why the nucleus is not stained in vital staining?
Signup and view all the answers
What is the term for substances that dissolve in tissue fluids?
What is the term for substances that dissolve in tissue fluids?
Signup and view all the answers
What is the primary product of benzene?
What is the primary product of benzene?
Signup and view all the answers
What is the function of chromophores in dyes?
What is the function of chromophores in dyes?
Signup and view all the answers
What is the main characteristic of most lysochromes?
What is the main characteristic of most lysochromes?
Signup and view all the answers
What type of reaction is involved in producing a colored substance in tissue using Schiff's reagent?
What type of reaction is involved in producing a colored substance in tissue using Schiff's reagent?
Signup and view all the answers
What is the type of chromophore group in basic and acid fuchsin?
What is the type of chromophore group in basic and acid fuchsin?
Signup and view all the answers
What is the function of auxochromes in dyes?
What is the function of auxochromes in dyes?
Signup and view all the answers
What is the purpose of enzyme histochemistry in tissue staining?
What is the purpose of enzyme histochemistry in tissue staining?
Signup and view all the answers
What is the term for tissues that can reduce ammonical silver solution to form visible deposits?
What is the term for tissues that can reduce ammonical silver solution to form visible deposits?
Signup and view all the answers
What type of dye is Basic fuchsin?
What type of dye is Basic fuchsin?
Signup and view all the answers
What is the source of carmine, a natural dye?
What is the source of carmine, a natural dye?
Signup and view all the answers
What is the characteristic of acidic or anionic dye?
What is the characteristic of acidic or anionic dye?
Signup and view all the answers
What is the characteristic of amphoteric dye?
What is the characteristic of amphoteric dye?
Signup and view all the answers
What is the purpose of using a pale or colorless solution in chemical production of a colored substance?
What is the purpose of using a pale or colorless solution in chemical production of a colored substance?
Signup and view all the answers
What is the type of dye that has affinity for both basic and acidic structures?
What is the type of dye that has affinity for both basic and acidic structures?
Signup and view all the answers
What type of staining technique is most commonly used?
What type of staining technique is most commonly used?
Signup and view all the answers
What is the term for tissues that can reduce ammonical silver solution to form visible deposits only with the addition of an extraneous reducer?
What is the term for tissues that can reduce ammonical silver solution to form visible deposits only with the addition of an extraneous reducer?
Signup and view all the answers
What type of staining requires an additional intermediate substance known as a mordant?
What type of staining requires an additional intermediate substance known as a mordant?
Signup and view all the answers
Which of the following fixatives favors basic dyes?
Which of the following fixatives favors basic dyes?
Signup and view all the answers
What is the purpose of an accentuator in tissue staining?
What is the purpose of an accentuator in tissue staining?
Signup and view all the answers
What is the role of an accelerator in tissue staining?
What is the role of an accelerator in tissue staining?
Signup and view all the answers
What is the purpose of a trapping agent in tissue staining?
What is the purpose of a trapping agent in tissue staining?
Signup and view all the answers
Which of the following is an example of a colorless leucobase?
Which of the following is an example of a colorless leucobase?
Signup and view all the answers
What is the purpose of differentiation in tissue staining?
What is the purpose of differentiation in tissue staining?
Signup and view all the answers
What is the effect of fixation on tissue staining?
What is the effect of fixation on tissue staining?
Signup and view all the answers
Study Notes
The Theory of Staining
- Tissues are transparent and colorless, making it difficult to distinguish different structures when examined with a light microscope.
- Histological techniques are used to distinguish tissue components, which can cause changes in the tissue through alteration of contrast or color.
Alteration of Contrast
- Phase contrast and polarized microscope can be used to make parts of the tissue appear grey or black.
- Impregnation methods can also be used to alter the contrast of tissue components.
Alteration in Color (Histological Staining)
- Histological staining involves the production of colors in tissue through dye-staining.
- The coloration is due to the absorption of light by the dye.
- A satisfactory staining method should combine high sensitivity and specificity.
- Sensitivity refers to the capacity of the stain to demonstrate a tissue substance in low concentration.
- Specificity or selectivity refers to the ability to discriminate between individual tissue components.
Staining Processes
- Vital Staining: Living cells can be stained by dissociation in the staining fluid (supra-vital) or by injection of dye into the living organism (intra-vital).
- Elective Solubility: Based on the solubility of the stain in tissue fluids, substances that dissolve in tissue are known as lysochromes.
- Chemical Production of Colored Substance in Tissue: Using a pale or colorless solution that reacts with tissue components to produce colored substances.
- Metallic Impregnation: Metallic compounds are reduced by tissues to produce opaque, black deposits.
- Staining with Dyes: Most staining techniques belong to this group, involving the use of natural or synthetic dyes.
Staining with Dyes
- Types and Structure of Dyes: There are two main types of dyes: natural dyes (e.g., carmine and haematoxylin) and synthetic dyes.
- Chromophores: Are the color-bearing chemical groups in the compound, which are classified into three main types: quinonoid, azo-coupling, and nitro group.
- Auxochromes: Are the ionizing groups that increase the intensity of the color, which are either acidic or basic.
- Dye Characteristics: Dyes can be basic, acidic, neutral, or amphoteric, depending on the number of basic or acidic auxochromes they contain.
- Modifiers: Additional chemical groups that alter the color of the dye or make it deeper.
Mode of Action of Dye Staining
- Chemical Dye Staining: Dye and tissues react together at the ordinary pH range, resulting in electropositive stain units combining with electronegative tissues and vice versa.
- Physical Dye Staining: Dye combines with tissues by adsorption, which is affected by physical factors such as density and permeability.
- Staining Techniques: There are four main staining techniques: progressive, regressive, direct, and indirect staining.
General Factors in Tissue Staining
- Effect of Fixation: Fixation can assist or hinder tissue-dye interaction, and may extract some tissue substances making subsequent staining ineffective.
- Accentuators: Substances used to increase the staining power and selectivity of dyes, but differ from mordants.
- Accelerators: Act like accentuators, used in metallic impregnation for the nervous system.
- Trapping Agents: Hold dyes in combination with tissues or bacteria, preventing them from escaping during differentiation.
- Differentiation: De-staining of over-stained tissue in regressive technique, brought about by washing, oxidizing agents, mordants, or dyes acting as differentiators.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the principles of histological staining techniques used to distinguish tissue components under a light microscope. It discusses alteration of contrast and color through different methods.
