Techniques In Pathology Flashcards
What are the commonly used techniques in the examination of tissues in pathology?
Light microscopy, histochemistry, immunohistochemistry, electron microscopy, flow cytometry, tissue culture, molecular pathology techniques.
What are the techniques used to overcome the limitations of light microscopy?
Dark field illumination and phase contrast microscopy.
What is the purpose of tissue fixation in histopathology
To preserve biological tissues from decay due to autolysis or putrefaction
Name two common methods for tissue processing before staining in histopathology
Paraffin section technique and frozen section technique.
What are the properties of an ideal fixative
Prevents autolysis, hardens tissue, inactivates infectious agents, stabilizes tissue components, enhances avidity for dyes.
List some undesirable effects of tissue fixation.
Alteration of protein structure, tissue component solubility, tissue shrinkage, DNA and RNA degradation.
What factors affect the process of fixation
Volume, access of fixative to tissues, time, temperature, buffer, pH.
What are the types of fixatives used in pathology?
Aldehydes, alcohols, mercurial, oxidizing agents, picrates.
What is the most commonly used fixative in pathology?
10% buffered formal saline or formalin.
What are the steps in tissue processing
Fixation, grossing, processing, embedding, microtomy, staining, mounting
What is the purpose of grossing in tissue processing?
To obtain good and accurate results by taking appropriate sections based on sample type and clinical indication.
What are the three basic steps in processing FFPE (Formalin Fixed Paraffin Embedded) tissue
Dehydration, clearing, infiltration
What is the function of the haematoxylin and eosin (H&E) stain
It is used in histology and histopathology to demonstrate normal and abnormal tissue components.
What is a frozen section used for in pathology?
Quick diagnosis, examination of resection margins, and preservation of fat and antigens.
What is histochemistry
technique for visualizing biological structures by identifying chemical components of tissues using stains and indicators
Give examples of histochemical techniques
Perls’s reaction, Von Kossa technique, Sudan black technique, Congo Red, PAS/PASD reaction, Ziehl–Neelsen Stain, Grocott for fungi.
What is immunohistochemistry (IHC)?
technique for identifying cellular or tissue constituents by means of antigen-antibody interactions
What are the two methods of immunohistochemistry?
Direct and indirect method
How does the direct method in immunohistochemistry work?
The primary antiserum is conjugated directly with a tracer molecule like horseradish peroxidase.
How does the indirect method in immunohistochemistry work
A secondary tracer-conjugated antibody binds to the primary antibody which is attached to the antigen.
What is immunofluorescence used for
Detecting antigens in tissue by using fluorescent-labeled antibodies
What are the two methods of immunofluorescence?
Direct immunofluorescence and indirect immunofluorescence.
Name some diseases where immunofluorescence is used
Lupus, pemphigus, pemphigoid, dermatitis herpetiformis, glomerular diseases.
What is electron microscopy (EM)?
technique for obtaining high-resolution images of specimens using a beam of accelerated electrons.
