Lecture 3 - From Specimen to Report II Flashcards
What is the primary objective of embedding in the histological process?
Embedding aims to create a “wax block” with tissue oriented for sectioning, ensuring correct orientation for optimal viewing.
Why is correct orientation crucial during embedding, and what exceptions exist for the placement of tissues in molds?
Correct orientation is essential for optimal sectioning. Exceptions include tubular structures, which should have the lumen perpendicular to the base.
What is the importance of sectioning (microtomy), and what thickness is typically desired for tissue sections?
Sectioning is crucial for microscopic examination. Tissue sections should be thin enough (around 4um) to allow light to pass through for optimal viewing.
How is a ribbon of wax sections produced, and why might these ribbons appear wrinkly?
The microtome produces a ribbon of wax sections held vertically. These ribbons may appear wrinkly and should be smoothed by floating them in a warm water bath.
Describe the process of mounting sections on a microscope slide after microtomy.
Sections are lifted onto a clean slide from a water bath, drained, and dried. Coating with substances like albumin may improve adhesion, and slides are then ready for further processing.
Why is rehydration necessary before staining tissue sections, and what is the typical rehydration protocol?
Rehydration removes wax from tissue sections, allowing aqueous dyes to penetrate. The protocol includes steps like xylene and alcohol immersion.
What are the aims of staining in histology, and what is the commonly used routine stain for general morphology?
Staining aims to make cell structure visible, show variation, and indicate chemical nature. H&E (Hematoxylin and Eosin) is a routine stain for general morphology.
What natural dye stains nuclei blue/purple, and what synthesised chemical is used to stain other tissue structures shades of pink?
Hematoxylin stains nuclei blue/purple, and Eosin, synthesized from chemicals, stains other tissue structures pink.
Why is mounting under a coverslip important, and what is the common mounting media in histopathology?
Mounting under a coverslip provides a clear view and protection. The common mounting media is DPX, a hydrophobic synthetic polystyrene resin.
What is the refractive index of the mounting media, and why is it crucial for optimal viewing?
The mounting media should have a refractive index close to glass, coverslip, slide, and tissue for optimal viewing.
What does a histopathology report typically include, and why is it an essential part of the diagnostic process?
A histopathology report includes specimen details, macroscopic and microscopic reports, SNOMED codes, patient and consultant details. It is essential for diagnosis and treatment decisions.
What are the components of quality assurance in histopathology labs, and why are they crucial?
Quality assurance involves internal checks, staining control slides, and adherence to accreditation standards. They ensure accuracy and reliability in lab processes.
What is the role of levels in slide review, and what additional investigations might be recommended by a histopathologist?
Levels produce additional sections cutting deeper into the block. Additional investigations may include histochemistry, immunocytochemistry, and in-situ hybridization.
What is the purpose of cryo-techniques in histology, and how do they differ from traditional embedding?
Cryo-techniques allow rapid freezing for urgent samples, preserving enzyme activity. Unlike traditional embedding, cryo-sections are cut without embedding in wax.
What are the advantages and disadvantages of cryo-techniques in histology?
Advantages include rapid results and preservation of enzyme activity. Disadvantages include limited block size, potential for incomplete freezing artifacts, and time-consuming sectioning.
