Techniques In Pathology

Question 1

What are the commonly used techniques in the examination of tissues in pathology?

Answer 1

Light microscopy, histochemistry, immunohistochemistry, electron microscopy, flow cytometry, tissue culture, molecular pathology techniques.

Question 2

What are the techniques used to overcome the limitations of light microscopy?

Answer 2

Dark field illumination and phase contrast microscopy.

Question 3

What is the purpose of tissue fixation in histopathology

Answer 3

To preserve biological tissues from decay due to autolysis or putrefaction

Question 4

Name two common methods for tissue processing before staining in histopathology

Answer 4

Paraffin section technique and frozen section technique.

Question 5

What are the properties of an ideal fixative

Answer 5

Prevents autolysis, hardens tissue, inactivates infectious agents, stabilizes tissue components, enhances avidity for dyes.

Question 6

List some undesirable effects of tissue fixation.

Answer 6

Alteration of protein structure, tissue component solubility, tissue shrinkage, DNA and RNA degradation.

Question 7

What factors affect the process of fixation

Answer 7

Volume, access of fixative to tissues, time, temperature, buffer, pH.

Question 8

What are the types of fixatives used in pathology?

Answer 8

Aldehydes, alcohols, mercurial, oxidizing agents, picrates.

Question 9

What is the most commonly used fixative in pathology?

Answer 9

10% buffered formal saline or formalin.

Question 10

What are the steps in tissue processing

Answer 10

Fixation, grossing, processing, embedding, microtomy, staining, mounting

Question 11

What is the purpose of grossing in tissue processing?

Answer 11

To obtain good and accurate results by taking appropriate sections based on sample type and clinical indication.

Question 12

What are the three basic steps in processing FFPE (Formalin Fixed Paraffin Embedded) tissue

Answer 12

Dehydration, clearing, infiltration

Question 13

What is the function of the haematoxylin and eosin (H&E) stain

Answer 13

It is used in histology and histopathology to demonstrate normal and abnormal tissue components.

Question 14

What is a frozen section used for in pathology?

Answer 14

Quick diagnosis, examination of resection margins, and preservation of fat and antigens.

Question 15

What is histochemistry

Answer 15

technique for visualizing biological structures by identifying chemical components of tissues using stains and indicators

Question 16

Give examples of histochemical techniques

Answer 16

Perls’s reaction, Von Kossa technique, Sudan black technique, Congo Red, PAS/PASD reaction, Ziehl–Neelsen Stain, Grocott for fungi.

Question 17

What is immunohistochemistry (IHC)?

Answer 17

technique for identifying cellular or tissue constituents by means of antigen-antibody interactions

Question 18

What are the two methods of immunohistochemistry?

Answer 18

Direct and indirect method

Question 19

How does the direct method in immunohistochemistry work?

Answer 19

The primary antiserum is conjugated directly with a tracer molecule like horseradish peroxidase.

Question 20

How does the indirect method in immunohistochemistry work

Answer 20

A secondary tracer-conjugated antibody binds to the primary antibody which is attached to the antigen.

Question 21

What is immunofluorescence used for

Answer 21

Detecting antigens in tissue by using fluorescent-labeled antibodies

Question 22

What are the two methods of immunofluorescence?

Answer 22

Direct immunofluorescence and indirect immunofluorescence.

Question 23

Name some diseases where immunofluorescence is used

Answer 23

Lupus, pemphigus, pemphigoid, dermatitis herpetiformis, glomerular diseases.

Question 24

What is electron microscopy (EM)?

Answer 24

technique for obtaining high-resolution images of specimens using a beam of accelerated electrons.

Question 25

What are some uses of electron microscopy in pathology

Answer 25

Diagnosing small round cell tumors, renal biopsies, nerve and muscle biopsies, bullous skin diseases, liver biopsies.

Question 26

What is molecular pathology

Answer 26

The study and diagnosis of disease through the examination of molecules within organs, tissues, or bodily fluids

Question 27

Name some techniques used in molecular pathology.

Answer 27

Southern blotting, polymerase chain reaction (PCR), fluorescent in-situ hybridization (FISH).

Question 28

What are the applications of molecular pathology?

Answer 28

Identifying inherited diseases, detecting infectious diseases, identifying genetic aberrations in tumors.

Question 29

What is cytogenetics

Answer 29

The study of chromosomes, combining cytology and genetics to understand inherited variations.

Question 30

When is cytogenetics indicated

Answer 30

For soft tissue tumors, mesotheliomas, unusual tumors, and poorly differentiated tumors.

Question 31

Q: What are the indications for flow cytometry

Answer 31

Ploidy and S phase analysis for conditions like hydatidiform mole, carcinomas, and for cell surface markers analysis in lymphomas and leukemias

Question 32

What is the importance of antigen retrieval procedures in immunohistochemistry

Answer 32

They help in restoring antigenicity lost during tissue fixation and embedding.

Question 33

How does temperature affect immunohistochemistry?

Answer 33

It can affect the immunoreactivity of antigens and the stability of antibodies.

Question 34

Why is paraffin embedding used in histopathology?

Answer 34

support tissue structures during sectioning for microscopic examination.

Question 35

What does the term “FFPE” stand for

Answer 35

Formalin Fixed Paraffin Embedded.

Question 36

What is the importance of drying slides in the oven during tissue processing?

Answer 36

To remove moisture and ensure proper adherence of tissue sections to the slides before staining.