Histopathology, Cytopathology and Blood Banking (Paper- III): Viva Prep

THE STATE MEDICAL FACULTY OF BANGLADESH

3rd Year Final Examination of Diploma in Medical Technology Course, January-2023

Group: Laboratory Medicine

Subject: Histopathology, Cytopathology and Blood Banking (Paper- III)

Full Marks: 100

Pass Marks: 50

 Q-01

(a) Tissue Processing:

Tissue processing refers to a series of steps involved in preparing biological tissues for microscopic examination. The process includes fixation, dehydration, clearing, and embedding, ultimately leading to the creation of thin sections that can be stained and observed under a microscope.

Steps of Tissue Processing:

Fixation: Preservation of tissue structure using fixatives.

Dehydration: Removal of water from tissues using alcohol.

Clearing: Substitution of alcohol with a clearing agent.

Embedding: Infiltration of tissues with a supporting medium, usually paraffin.

Sectioning: Cutting thin sections from the embedded tissue block.

Staining: Application of dyes to enhance contrast for microscopic examination.

(b) Fixative:

A fixative is a chemical substance used to preserve the structure of biological tissues by preventing decomposition. Common fixatives include:

Formalin (10% formaldehyde):

Alcohol (e.g., ethanol):

Bouin's solution:

Carnoy's fluid:

Zenker's fluid:

(c) Preservative:

A preservative is a substance that prevents decay or spoilage. In the context of pathology, it is often used to maintain the integrity of specimens. Some preservatives include:

Formalin (as a fixative and preservative):

Sodium azide:

Mercuric chloride:

Thymol:

Paraformaldehyde:

(d) Ideal Blood Donor Criteria:

Good general health

Adequate hemoglobin levels

Proper weight and age

No history of high-risk behaviors

Negative for infectious diseases (e.g., HIV, hepatitis)

No recent history of travel to high-risk areas

(e) Blood Groups and Cross Matching:

Major blood groups: A, B, AB, O (based on ABO system) and Rh-positive or Rh-negative (based on Rh system).

Cross matching involves mixing donor and recipient blood samples to check for compatibility, preventing adverse reactions during transfusions.

Q-02

(a) Anticoagulant:

An anticoagulant is a substance that prevents blood from clotting. Common anticoagulants and their indications include:

Heparin: Used in the prevention of blood clotting during medical procedures.

Warfarin: Used for long-term anticoagulation, often for conditions like atrial fibrillation.

Aspirin: Acts as an antiplatelet agent, preventing platelets from forming clots.

Edoxaban: A newer oral anticoagulant used to reduce the risk of stroke and systemic embolism.

Dabigatran: Another oral anticoagulant used to prevent blood clots.

(b) Benign vs. Malignant Tumor:

Benign Tumor: Typically slow-growing, well-defined boundaries, non-invasive, and does not spread to other parts of the body.

Malignant Tumor: Invasive, potentially fast-growing, capable of spreading to surrounding tissues or distant organs (metastasis).

(c) Cytology, Cytopathology, and Histopathology:

Cytology: The study of cells, often involving the examination of individual cells for abnormalities or diseases.

Cytopathology: A branch of pathology focusing on the study of diseases at the cellular level.

Histopathology: The study of diseases by examining tissues at the microscopic level, assessing cellular and structural changes.

(d) Procedure of Washing RBC:

RBC washing involves centrifugation and removal of plasma and supernatant, followed by resuspension and repeated washing with an isotonic solution to eliminate unwanted substances.

(e) Carcinoma in Situ:

Refers to cancerous cells that are present only in the layer of cells where they developed and have not invaded surrounding tissues. It is considered a pre-invasive stage of cancer.

Q-03

(a) Coplin Jar:

A Coplin jar is a glass or plastic container used in laboratories for various purposes, primarily in histology and cytology. Its uses include holding and immersing slides in various solutions during staining procedures.

(b) Direct and Indirect Coombs Test:

Direct Coombs Test: Detects antibodies bound to the surface of red blood cells (RBCs) in autoimmune hemolytic anemia.

Indirect Coombs Test: Detects antibodies in the plasma that may react with donor RBCs, important in blood transfusions and Rh incompatibility during pregnancy.

(c) Staining:

Staining is a technique used to enhance the visibility of cells or tissues under a microscope by imparting color. For a histopathological slide, commonly used stains include hematoxylin and eosin (H&E). The procedure involves immersing the slide in hematoxylin to stain nuclei, followed by eosin to stain cytoplasm.

(d) Maintaining Register Book in Blood Bank:

A register book in a blood bank records information about donors, recipients, blood components, and transfusions. Its importance lies in ensuring traceability, accurate documentation, and adherence to regulatory requirements, helping in the monitoring and control of blood transfusion processes.

(e) FNAC (Fine Needle Aspiration Cytology):

FNAC is a diagnostic procedure involving the extraction of cellular material from a tissue using a fine needle for cytological examination. To prepare a slide, the collected material is smeared onto a glass slide, fixed, and stained for microscopic analysis.

Q-04

(a) Staining Procedure of Pap's Smear:

Pap smear staining involves fixing and staining cervical cells to detect abnormalities. Steps include fixation, dehydration, clearing, and staining with Papanicolaou stain, which highlights cellular features for cytological examination.

(b) Block Making:

In histopathology, after tissue processing, embedding in paraffin wax forms a block. Block making involves embedding the processed tissue in molten paraffin wax and allowing it to solidify, creating a block for sectioning.

(c) Indications of Blood Transfusion:

Blood transfusion is indicated in conditions such as severe anemia, blood loss from surgery or trauma, certain cancers, bleeding disorders, and during some medical treatments.

(d) Paraffin Bath:

A paraffin bath is a device used to melt and maintain paraffin wax at a controlled temperature. Steps of paraffin sections involve immersing tissue blocks in molten paraffin to embed them for sectioning.

(e) Microtome:

A microtome is a device used to cut thin sections of tissues for microscopic examination. Mechanical parts include the knife holder, feed mechanism, and advance and coarse advance knobs.

Q-5

(a) Water Bath:

A water bath is a laboratory equipment that uses water to maintain a constant temperature for incubation, heating, or cooling of samples.

(b) Decalcification:

The process of removing calcium salts from tissues to make them more pliable for sectioning and staining.

(c) Anticoagulant:

A substance that prevents blood clotting. It is essential for preserving blood samples for various laboratory tests.

(d) 40% Formalin:

A formaldehyde-based solution used as a fixative and preservative in pathology to preserve tissues for microscopic examination.

(e) Universal Donor:

Refers to individuals with blood type O-negative, as they can donate blood to individuals of any blood type.

Note: Each question and its subparts are treated independently for oral examination responses. If the examiner asks for elaboration, additional details should be provided.