Lec 5: Staining Flashcards
The process that renders different tissue components more visible through variation in color
Staining
Treating tissues or cells with a series of Reagents to acquire a color
Staining
Chemical substances used to achieve visible color contrast in the microscopic picture of a prepared tissue
Stains
Purpose of staining (3)
- Outlines tissues and cell components
- Identification of tissues
- Establishes the presence or absence of disease processes
Common Staining Methods:
(and their department)
- H&E - Histopathology
- Gram’s stain & Ziel-Neelsen - Microbiology
- Romanowsky (wright) - Hematology
- Giemsa - Parasitology
- Papanicolaou - Cytology
- Purpose for heat fixing
- Temperature and time for heat fixing
- To remove paraffin wax
- 60°C for at least 30 minutes
CYTOPLASMIC STAINING
1. the color of cytoplasm when stain is below pH 3?
2. The color of cytoplasm when stain is above pH 6?
- Reddish / orange
- Bluish / purple
Chemicals with an essentially aromatic benzene ring compound
Dyes / stains
Dyes/stains possess the twin properties of ___.
- color band
- ability to bind to tissues
The group on the benzene ring which confers color
Chromophore
A benzene derivative containing chromophoric groups
Chromogen
It is a chromophore where two hydrogen atoms on the benzene ring have been replaced by oxygen atoms.
Quinone group
A chromophore that are interbenzene bonds
Quinone-imine group
The group responsible for tissue to bind firmly to a given dye
Auxochrome
The combination of chromophore & auxochrome
Dye / stain
It stains basic components such as cytoplasm and acidophil granules
Acidic dye
Stains acidic components such as nucleus and basophil granules
Basic dye
- Consist of mixture mixtures of basic and acidic dyes
- It depends on the ph of the solution
- Stains both cation and anion
Neutral dye
It acts by combining with the metal, thus breaking the latter’s union with the tissue for cell components
Acid differentiators
It acts by oxidizing the dye to a colorless substance
Oxidizing differentiators
A substance which enhances the combination of the dye with the tissues forming a colored lake tissue mordant-dye complex
Mordant
A substance that can cause no chemical union between the tissue and the dye
Accentuator
It does not participate in the staining reaction but hastens the speed or the intensity and selectivity of the dye
Accentuator
It increases the rate of the staining action
Accelerator
