Histology Chapter 1 Flashcards

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Questions and Answers

What is histology and the underlying theme of this course?

Histology is the study of the tissues of plants and animals. Principle of complementarity of structure and function.

What is histopathology?

The microscopic study of diseased tissue in which compromised function is linked to abnormal cell and/or tissue structure.

What is one issue that occurs when preparing tissues on a microscope slide?

Artifacts - abnormalities of structure brought about through tissue processes.

What are the 8 steps of tissue preparation?

Fixation, Dehydration, Clearing, Infiltration, Embedding, Sectioning, Mounting, Staining. Signup and view all the answers

What is fixation in tissue slide preparation?

To kill cells and preserve tissue structure. Signup and view all the answers

What is dehydration in tissue preparation?

The removal of water in an ascending series of alcohol dilutions. Signup and view all the answers

What happens during the clearing step?

Replaces the alcohol with a solvent that is miscible in embedding medium. Signup and view all the answers

What happens during infiltration?

The tissue is placed in embedding medium in its liquid form. Signup and view all the answers

What happens during embedding?

The embedded tissue is allowed to solidify. Signup and view all the answers

What happens during sectioning?

Tissue is placed on a microtome. Signup and view all the answers

What is mounting?

Tissue sections are placed on glass slides. Signup and view all the answers

What is staining?

Tissue sections are stained to add contrast and color. Signup and view all the answers

Artifacts are caused by cell shrinkage; what is one way to prevent this?

The use of frozen tissue and a cryostat to section it will prevent cell shrinkage. Signup and view all the answers

What is basophilic staining?

Having an affinity for basic (cationic) dyes. Signup and view all the answers

What is acidophilic staining?

Having an affinity for acidic (anionic) dyes. Signup and view all the answers

What is hematoxylin?

An acidic substance derived from the bark of the logwood tree; it is a basic dye that stains nuclei. Signup and view all the answers

What is eosin?

A synthetic, acidic dye that stains cytoplasm and other basic components red or pink. Signup and view all the answers

What are the most commonly used dyes in bright-field microscopy?

Hematoxylin and eosin (H&E). Signup and view all the answers

What is enzyme histochemistry?

Allows one to identify and localize the sites of activity of particular enzymes. Signup and view all the answers

What are 4 basic components that all microscope systems have in common?

Illuminating system, system to hold the specimen in the beam, imaging system, image translating system. Signup and view all the answers

What is immunohistochemistry used for?

Labeled antibodies are used to locate specific antigens. Signup and view all the answers

What is direct immunohistochemistry?

A labeled antibody is used to react with a specific antigen. Signup and view all the answers

What is indirect immunohistochemistry?

An unlabeled primary antibody is used to react with a specific antigen and a labeled secondary antibody. Signup and view all the answers

What are four components of compound light microscopes?

Illuminating system (electric lamp), condenser, objective lens, eyepiece or ocular lens. Signup and view all the answers

What is the most routinely used type of compound light microscope?

Bright-field. Signup and view all the answers

How does phase-contrast microscopy work?

Uses differences in refractive index to distinguish structures. Signup and view all the answers

What type of light is used in fluorescence microscopy?

UV light source excites fluorescent molecules. Signup and view all the answers

What structures can you see with fluorescence microscopy?

Fluorescence microscopy can be used to differentiate DNA in the nucleus and RNA in the cytoplasm. Signup and view all the answers

Study Notes

Overview of Histology

Histology is the study of tissues in plants and animals, emphasizing the principle of complementarity where structure and function are interrelated.

Histopathology

Histopathology involves microscopic examination of diseased tissues, connecting compromised functions with abnormal cellular structures.

Tissue Preparation Artifacts

Artifacts are structural abnormalities caused during tissue preparation, often appearing as tissue folding.

Steps of Tissue Preparation

The preparation of tissue slides involves eight critical steps:
- Fixation
- Dehydration
- Clearing
- Infiltration
- Embedding
- Sectioning
- Mounting
- Staining

Fixation

Fixation preserves tissue architecture and kills cells to maintain structural integrity.

Dehydration

Dehydration entails the removal of water from tissues using a gradient of alcohol solutions.

Clearing

Clearing replaces alcohol with a solvent compatible with the embedding medium.

Infiltration

Infiltration involves saturating the tissue with a liquid embedding medium.

Embedding

Embedding allows the infiltrated tissue to harden and maintain its shape for sectioning.

Sectioning

Sectioning utilizes a microtome to slice embedded tissue into thin sections for mounting.

Mounting

Tissue sections are placed on glass slides for examination.

Staining

Staining enhances tissue contrast and coloration, vital for visual differentiation during microscopy.

Preventing Artifacts

To minimize artifacts from cell shrinkage, frozen tissue can be sectioned using a cryostat.

Staining Affinities

Basophilic staining targets basic cationic dyes, primarily highlighting cell nuclei.
Acidophilic staining shows affinity for acidic anionic dyes, typically coloring cytoplasm.

Common Dyes

Hematoxylin, derived from logwood, stains nuclei and acidic structures in shades of blue, purple, or black.
Eosin is a synthetic dye that imparts red or pink hues to cytoplasm and other basic elements.

Microscopy Techniques

Hematoxylin and eosin (H&E) are the most frequently employed dyes in bright-field microscopy.
Enzyme histochemistry enables specific enzyme location and activity visualization using fresh frozen tissue and marker compounds.
Basic components of microscope systems include illuminating systems, specimen holders, imaging systems, and translation systems.

Immunohistochemistry

Immunohistochemistry employs labeled antibodies to detect specific antigens.
Direct immunohistochemistry uses a labeled antibody for antigen targeting.
Indirect immunohistochemistry involves an unlabeled primary antibody that binds to an antigen, followed by a labeled secondary antibody.

Compound Light Microscopes

Key components include an illuminating system, condenser, objective lens, and eyepiece.
Bright-field microscopy is the most commonly used type.

Advanced Microscopy

Phase-contrast microscopy capitalizes on refractive index differences for structural differences.
Fluorescence microscopy utilizes UV light to view specimens, often those treated with immunohistochemical methods, effectively differentiating nucleic acids like DNA and RNA.

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Description

Explore the fundamentals of histology and its methodologies in this quiz. Learn the essential definitions and concepts, including the significance of histopathology. This is a crucial chapter for anyone studying biology or medicine.