Histology Specimen Handling Techniques

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Questions and Answers

What is the purpose of tissue fixation during the preparation of histopathological specimens?

To stabilize the tissue and prevent autolysis and putrefaction (correct)

To embed the tissue in a solid medium for storage

To enhance the color of the tissue for better visibility

To remove excess moisture from the specimen

Which step in tissue processing involves cutting the specimen into ultra-thin sections for microscopic examination?

Embedding

Sectioning (correct)

Fixation

Staining

What is the main reason for using different staining techniques in histopathology?

To assess the overall health of the specimen

To determine the age of the specimen

To highlight specific cell structures or tissue components (correct)

To prepare the specimen for transportation

During which stage of intra-laboratory preparation is tissue dehydrated, cleared, and embedded?

Processing Signup and view all the answers

What is essential for ensuring the quality control of pathology specimens during both pre-laboratory and intra-laboratory phases?

Proper identification, labeling, and documentation of the specimen Signup and view all the answers

What is the main purpose of hematoxylin in H&E staining?

To stain nuclei blue/purple. Signup and view all the answers

What does Masson's Trichrome staining differentiate between?

Muscle fibers, collagen, and nuclei. Signup and view all the answers

Which step involves applying dyes to enhance the visibility of tissue structures?

Staining Signup and view all the answers

What is the purpose of periodic acid-Schiff (PAS) staining?

To highlight carbohydrates in tissues. Signup and view all the answers

Which of the following is NOT a part of the key histopathological steps?

Embedding in resin Signup and view all the answers

What additional diagnostic information can immunohistochemistry (IHC) provide?

Specific antigens related to disease processes. Signup and view all the answers

Which step in histopathology involves stabilizing and preserving tissue after collection?

Fixation Signup and view all the answers

Why is staining considered critical in histopathological analysis?

It is essential for exposing cellular structures under a microscope. Signup and view all the answers

What is the primary purpose of fixation in biopsy preparation?

To prevent degradation of cellular detail Signup and view all the answers

What is the significance of decalcification in the preparation of bone samples?

It softens the bones for easier sectioning Signup and view all the answers

During the processing of biopsies, which step occurs immediately after fixation?

Dehydration Signup and view all the answers

Which staining technique is commonly used after sectioning tissues for microscopic examination?

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

What is a critical factor to ensure accuracy in diagnosing tissues?

Proper orientation during embedding Signup and view all the answers

Which of the following statements best describes the processing of bone and biopsy tissues?

They follow similar processing steps but have distinct handling requirements. Signup and view all the answers

What purpose does sectioning serve in the examination of tissues?

To allow for easier microscopic inspection of thin layers Signup and view all the answers

Why is it important to handle biopsies carefully during preparation?

To ensure they do not degrade before fixation Signup and view all the answers

Study Notes

Pre-laboratory Specimen Handling

Samples are collected via surgical procedures or autopsies.
Specimens require proper identification, labelling, and documentation.
Tissues are placed in an appropriate medium or fixative to prevent degradation

Intra-laboratory Tissue Handling and Preparation

Trimming: Tissue is trimmed to the appropriate size for processing.
Fixation: Tissue is stabilized to prevent decomposition through a process called autolysis and putrefaction.
Processing: Tissue undergoes dehydration, clearing, and embedding stages.
Embedding: Tissue is embedded in a solid medium (paraffin wax) to facilitate slicing into thin sections.
Sectioning: Extremely thin slices are cut (around 3 to 5 micrometers thick) for examination with a microscope.
Staining: Tissues are stained to highlight specific cell structures or components.

Common Staining Techniques

Hematoxylin and Eosin (H&E Staining): Hematoxylin stains the nuclei blue/purple, while Eosin stains the cytoplasm and extracellular matrix pink/red. This is used to visualize general tissue morphology.
Periodic Acid-Schiff (PAS Staining): Stains carbohydrates, highlighting basement membranes, fungal organisms, and glycogen storage diseases
Masson's Trichrome: Differentiates muscle fibers (red), collagen (blue/green), and nuclei (black), mainly used for liver fibrosis.
Immunohistochemistry (IHC): Uses antibodies to target specific antigens in the tissue to identify specific cell types, proteins, and receptors for cancer diagnosis and subtyping.

Summary of Key Histopathological Steps

Specimen Collection: Proper handling and labeling.
Fixation: Stabilization and preservation of tissue.
Processing: Dehydration, clearing, and embedding of the specimen.
Sectioning: Thin slices are cut for microscopic examination.
Staining: Application of dyes to highlight tissue structures.
Examination: Analysis under a microscope for diagnosis.

Bone Decalcification

Bone requires decalcification for sectioning, as it is too hard to cut.
Decalcified bone is then embedded in paraffin wax for sectioning.
Decalcification is achieved by using acids to dissolve the calcium salts in the bone.

Biopsy Preparation

Biopsies are small tissue samples taken from suspicious areas.
Biopsies must be handled carefully to maintain their structure.
Fixation: Biopsies are placed in a fixative (like formalin) immediately after removal to prevent degradation.
Processing: Biopsies undergo the same processing steps as other tissues (dehydration, clearing, and embedding).
Sectioning: Embedded biopsy can be sliced into thin sections for microscopic examination.

Special Considerations

Orientation or positioning: Both bone and biopsy samples require careful positioning for embedding to ensure informative areas are ready for examination under the microscope.
Staining: Sectioned bone and biopsy samples often require staining (H&E) for visualization of cellular structures to help identify abnormalities.

Key Points

Decalcification is essential for bone sectioning to soften it so it can be sliced.
Biopsies require rapid fixation to preserve cellular details.
Both bone and biopsy tissues are processed similarly, but require specific handling techniques to ensure accurate diagnosis.

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Description

This quiz covers essential techniques for specimen handling and preparation in histology, including proper identification, fixation, and staining methods. Learn the steps involved in trimming, embedding, and sectioning tissue for microscopic examination. Test your knowledge on common staining techniques such as H&E staining.