Histopathology Midterm

35問 • 2年前

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It is a process whereby a selected tissue specimen is immersed in a watch glass containing isotonic salt solution, carefully dissected or separated, and examined under the microscope, either unstained by phase contrast or bright field microscopy, or stained with differential dyes.

Teasing or Dissociation

Small pieces of tissue not more than one mm. in diameter are placed in a microscopic slide and forcibly compressed with another slide or with a cover glass

Squash Preparation (Crushing)

Process of examining sections or sediments, whereby cellular materials are spread lightly over a slide by means of a wireloop or applicator or by making an apposition smear with another slide.

Smear Preparation

Why is it important to perform correct methods of tissue preparation?

So that we obtain good slides for the microscopic examinations

With an applicator stick or a platinum loop, the material is rapidly and gently applied in a direct or zigzag line throughout the slide

Streaking

A selected portion of the material is transferred to a clean slide and gently spread into a moderately thick film by teasing the mucous strands apart with an applicator stick.

Spreading

Method to use for fresh sputum, bronchial aspirates and thick mucoid secretions

Spreading

It is done by placing a drop of secretions or sediment upon one slide and facing it to another clean slide

Pull-apart

Method to use for Serous fluid, conc. Sputum, enzymatic lavage samples from GIT and blood smears

Pull-apart

The surface of a freshly cut piece of tissue is brought into contact and pressed on to the surface of a clean glass slide, allowing the cells to be transferred directly to the slide for examination by phase contrast microscopy or stained for light microscopic study.

Touch Preparation (Impression smear)

When should you utilized Frozen Section?

It is utilized when a rapid diagnosis of the tissue is required

What are the commonly used methods of freezing?

Liquid nitrogen, Isopenthane cooled by liquid nitrogen, Carbon dioxide gas, Aerosol sprays

What is the disadvantage of using Liquid Nitrogen for freezing?

The soft tissue is liable to crack due to the rapid expansion of the ice w/in the tissue, producing ice crystals or freeze artifact.

In this method, the soft tissue is liable to crack due to the rapid expansion of the ice w/in the tissue, producing ice crystals or freeze artifact

Liquid nitrogen

It is adequate for freezing small pieces of tissue except muscle for histochemistry and during operative procedures

Aerosol sprays

The process of Tissue Processing

Numbering, Fixation, Dehydration, Infiltration, Embedding, Trimming, Section-Cutting, Staining, Mounting, Labelling

How do we do the numbering?

In numbering, the specimen number is preceded by either S (surgical), A (autopsy) or C (cytology). The year is also indicated. Example: S98-7677

What are the purpose of Fixation?

o Preserve the tissue- stop all cellular activities o Prevent breakdown of cellular elements o Prevents postmortem decomposition (autolysis) o Prevents putrefaction o Coagulate or precipitate protoplasmic substances

Postmortem decomposition is also known as

Autolysis

Why does tissues need to be fixed?

To preserve cells and tissue constituents and to prevent their degradation.

It is considered to be the longest phase in routine histopathology.

Fixation

Explain the two basic mechanisms in fixation?

There are two basic mechanism in fixation: •Additive fixation- chemical constituent of the fixative is taken in and becomes part of the tissue. •Non-Additive fixation- Fixing agent is not incorporated into the tissue.

It is the removal of Calciun or lime salts from bones or calcified tissues following fixation.

Decalcification

Purpose of this methof is to preserve the maximum enzyme activity at its localization.

Enzyme Histochemistry

It is for antibodies demonstration

Immunofluorescence and Immun

Types of Decalcifying agent

Acids, Chelating agent, Ion exchange resin, Electrophoresis

Energy and heat production within the body stops, and the body gradually starts to lose heat; body cools much faster on the exterior surface as compared to the interior of the body

Algor mortis

Post-mortem Lividity, Post-mortem Staining or Post-mortem Hypostasis, Post mortem suggillation appear within 0.5-2 hours after death and are fully developed by 6-12 hours cessation of blood circulation, which causes the blood to become stagnant, red blood cells begin to settle down due to gravity Dull purple-black spots called as “Tardieu Spots” gradually increase in size and appear more intensely coloured

Livor mortis

Shortening of the muscle fibres first to stiffen are the muscles of the eyelids then muscles in the neck region, lower jaw, facial muscles, chest muscles, upper limbs, abdominal muscles, and lower limbs. The fingers and toes, stiffen last

Rigor mortis (Death Stiffening or Cadaveric rigidity)

It begins at the point of death and continues from then on, until the body is skeletonized arise as a result of bacterial and entomological activity first external sign of putrefaction is seen as a greenish-black discolouration of skin in the stomach and abdominal region

Post mortem Decomposition/ putrefaction

When does liquefaction of tissues takes place?

5-10 days post-mortem

It takes place in dry and hot climates, dehydrates the body, may take 3 months to a year, formation of a dry and brittle layer over the body, and the body might appear shrivelled, often helps in the preservation of the body features

Mummification

formation/ saponification: different from the usual process of decomposition. This is observed in cases where the body is found in extremely moist, warm and lack of oxygen body is found to have a whitish, smeary, mouldy or putrid-smelling layer of fat, may take about 2 wks-2 months

Adipocere

Stage of decomposition in which the proteins of the body's cells are broken down and consumed by bacteria in anaerobic conditions

Maceration

Specimen care for biopsy

The specimen should be immediately placed in 10% formalin solution and be completely immersed

Translation(Pre-finals)

MAHATHIR ALPHA · 55問 · 2年前

Translation(Pre-finals)