Immunohistochemistry and Histology Quiz

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Questions and Answers

What is the primary role of secondary antibodies in immunohistochemistry?

To initiate the staining process.

To eliminate the need for primary antibodies.

To amplify the signal by binding to primary antibodies. (correct)

To directly visualize tissue structures.

What is the chemical process that occurs when DAB is oxidized in the presence of HRP?

It undergoes a reaction to form a brown precipitate. (correct)

It results in the formation of a blue precipitate.

It transforms into a colorless solution.

It creates a fluorescent compound.

What is the primary advantage of using tissue microarrays (TMAs) in histological studies?

They minimize the need for light microscopy.

They require larger volumes of tissue for analysis.

They can only analyze single tissue samples.

They allow for the simultaneous analysis of numerous tissue cores. (correct)

Which characteristic defines monocytes when examined in a human blood smear?

They are characterized by their large size and bean-shaped nucleus. Signup and view all the answers

What is a disadvantage of using DAB in immunohistochemistry?

It can produce a fading signal over time. Signup and view all the answers

What is the primary purpose of the sampling process in medical diagnosis?

To evaluate cellular morphology for treatment decisions Signup and view all the answers

Which statement correctly describes a characteristic of blood cells?

They can change shape based on water retention. Signup and view all the answers

What is the correct order of the histological image processing steps?

Sampling, Fixation, Processing, Embedding, Cutting, Staining Signup and view all the answers

How does DNA influence the protein synthesis process?

DNA determines RNA, which in turn determines the protein structure Signup and view all the answers

Why is it essential to use a longitudinal section of a cell for cancer staging?

To detect patches of disease that may be localized Signup and view all the answers

What is the focus of histology as a field of study?

The structure of cells and their changes over time Signup and view all the answers

In the context of cancer types and stages, what was established in a study conducted in 2015?

There is a correlation between blood vessel morphologies and breast cancer characteristics. Signup and view all the answers

Which statement accurately describes the difference between samples for cytopathology and biopsies?

Cytopathology focuses on individual cells, while biopsies preserve tissue structure. Signup and view all the answers

What is the primary purpose of fixation in tissue analysis?

To convert semi-liquid consistency of cells to semi-solid Signup and view all the answers

Which of the following statements about perfusion fixation is true?

This technique allows for a more uniform distribution of the fixative throughout the body. Signup and view all the answers

What are the main advantages of freezing tissues for analysis?

Rapid processing with minimal xative exposure Signup and view all the answers

What is a significant disadvantage of using frozen sections for tissue analysis?

They may not provide sufficient morphological detail. Signup and view all the answers

Which method of ordering fixation generally results in less morphological detail due to the removal of water?

Paraffin embedding Signup and view all the answers

How does paraformaldehyde differ from methanol in tissue preservation?

Paraformaldehyde maintains structure, while methanol causes degradation. Signup and view all the answers

What role does a microtome play in the tissue analysis process?

It cuts tissues into thin sections for examination. Signup and view all the answers

What happens if there are delays in fixation or concentration mistakes during the fixation process?

The tissues may face over-fixation or under-fixation, leading to losses. Signup and view all the answers

What is the purpose of the embedding step in tissue processing?

To support tissues in a substance allowing for easy sectioning. Signup and view all the answers

Which component of the staining process specifically binds to the nuclei of the tissue?

Hematoxylin Signup and view all the answers

What is the primary role of polyclonal antibodies in immunochemistry?

Recognize multiple different antigens of a protein Signup and view all the answers

Which staining technique is particularly useful for identifying connective tissue structures?

Trichrome stain Signup and view all the answers

What distinguishes immunofluorescence from other staining methods?

It emits light from the tissue sample Signup and view all the answers

What happens to the sample before the staining process begins?

It is embedded in paraffin wax Signup and view all the answers

Which staining method was developed by Camillo Golgi and is used to detect DNA and proteins?

Silver staining Signup and view all the answers

What is the key disadvantage of using polyclonal antibodies compared to monoclonal antibodies?

Tendency to bind to similar antigens causing complex staining Signup and view all the answers

What is the basic function of the chromogen in immunohistochemistry?

To enhance the visibility of stained antibodies Signup and view all the answers

What is the dehydrating agent used in the pre-staining process to remove the paraffin wax?

Xylene Signup and view all the answers

What color does eosin impart to the tissues during the histochemistry staining process?

Red Signup and view all the answers

Study Notes

Cell Morphology and Role in Tissues

Cellular morphology (shape) is crucial for cellular function within tissues
Protein function depends on its 3D structure
DNA dictates RNA production, which dictates protein structure
Environmental changes can alter cellular function
Some cells maintain fixed shapes, others adapt to environmental cues and interactions with neighbors
Cell shape and function can change based on the concentration of water it retains
Isotonic, hypertonic and hypotonic solutions affect cell shape and structure

Histology

Histology studies cell structure and changes
Tissue identification is possible by examining cell appearance (e.g., pancreatic islets)
Correlation of blood vessel morphology with breast cancer stages studied in 2015

Tissue Sampling and Preparation

Sampling involves extracting tissue samples for analysis
Fixation prevents tissue degradation
Processing prepares tissue for embedding
Embedding surrounds the tissue in a medium like paraffin
Cutting produces thin tissue sections (usually 2-10 microns)
Staining increases visibility of targeted cells

Sampling Techniques

Aspiration (e.g., amniocentesis, fine needle)
Frozen sections for rapid diagnosis
Scraping (e.g., Pap test)
Proper sample selection crucial for accurate diagnosis, particularly for diseases that develop in specific tissue areas

Biopsy

Biopsy preserves natural tissue structure
Cytopathology isolates individual cells, ignoring spatial relationships

Tissue Fixation

Fixation transforms semi-fluid tissue to semi-solid for analysis
Immersion involves submerging tissue in a fixative like formalin in a volume ratio significantly greater than the tissue

Tissue Perfusion

Perfusion injects fixative into the heart, allowing comprehensive tissue fixation

Tissue Processing

Reagent diffusion through tissues
Tissues are dehydrated, cleared, and infiltrated for preservation

Tissue Embedding

Paraffin method—tissue embedded in paraffin wax for section support

Tissue Cutting

Microtome cuts thin sections of tissue

Tissue Staining

Staining enhances visualization of cells/structures during microscopic examination.
Tissue pre-staining with various methods, including wax removal and alcohol rehydration

Immunohistochemistry (IHC)

IHC uses antibodies to target specific proteins
Polyclonal antibodies bind to multiple antigens. This method is tricky for specific targets
Monoclonal antibodies bind to single targets for more accurate results.
Visualisation via chromogens (e.g., DAB)

Tissue Microarrays (TMAs)

TMAs are paraffin blocks with multiple tissue cores. This method allows for multiple analyses

Human Blood Smear

Blood smear composition analysis observes cell types and structures (e.g., red blood cells, white blood cells)

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Description

Test your knowledge on immunohistochemistry and histology with targeted questions about secondary antibodies, DAB oxidation, and tissue microarrays. This quiz covers essential concepts in histological methods and their applications in medical diagnosis and cancer research.