Things to go over for Quiz # 1 from Lesson Content 1,2&3 (20 MCQ)

What is pathology?

The study of diseases, their causes, processes, development, and consequences.

What is histology?

The study of the microscopic structure of tissues.

What is cytopathology?

The examination of individual cells to diagnose disease.

What is histopathology?

The study of tissue changes caused by disease.

What are surgical specimens and autopsy specimens?

Surgical specimens are tissues removed during surgery; autopsy specimens are tissues taken during an autopsy to determine cause of death.

What is the process that the tissue samples go through?

Tissue processing, which includes fixation, dehydration, clearing, infiltration, and embedding.

What is biopsy?

The removal of a sample of tissue for examination.

Tissue specimens can be sent to the lab in what two different ways?

Formalin-fixed or fresh (unfixed).

What number is assigned when the specimen is received?

A unique specimen identification number called an accession number

What is the TAT for emergency, STAT, ASAP, and routine?

TAT: Turnaround time varies; emergency often less than 1 hour, STAT typically within hours, ASAP: within 4 hours, and routine within 24 hours to a few days.

What is fixation? What is the purpose of fixation?

Fixation is a process to preserve tissue structure; its purpose is to prevent decay and preserve morphology.

The fixation volume to the specimen should be how many times?

10 to 20 times the volume of the specimen

What is Ischemic time?

The time tissues are without adequate blood supply.

The pH of the fixation solution should be buffered at?

A neutral pH, typically around 7.0.

How can the fixation time be affected?

Factors include the size of the tissue and the type of fixative used.

What is the rate the tissue is fixed at?

Fixation typically occurs at a rate of approximately 1 mm per hour.

What is autolysis?

The self-digestion of cells or tissues by their own enzymes.

What is putrefaction?

The decomposition of organic matter (tissue), caused by bacterial action.

What is the primary goal for fixatives?

To preserve tissue morphology and prevent degradation.

List the fixing agent?

Formalin, alcohols, acetone, and picric acid.

What is the most common fixative used in histopathology labs?

Formalin.

What are the advantages and disadvantages of formalin?

Advantages include low cost and effective tissue preservation; disadvantages include potential formalin fumes and tissue shrinkage.

What is the picric acid safety?

Picric acid is explosive when dry and requires careful handling: Always keeping it wet with water, using it in a fume hood with appropriate PPE, avoiding contact with metal, and never letting it dry out or storing old samples

Go over the other fixatives with its advantages and disadvantages.

Other fixatives include alcohol (rapid fixation but can cause shrinkage) and acetone (fast fixation but less effective for morphology).

What is grossing and when is it performed?

Grossing is the initial examination and description of the specimen before sectioning.

Tissues that are 3-5mm are placed in a __?

In a routine fixative or 10% buffered formalin.

Tissues that are larger than 5mm are placed in a __?

Tissue cassette (a large slotted plastic container) of fixative

What is decalcification? Does this step always happen with all the tissue specimens?

Decalcification is the process of removing calcium deposits; it does not occur with all specimens.

Name the decalcifying agents.

EDTA, hydrochloric acid, and formic acid.

What is the volume times of decalcifying agent to the tissue?

20:1 (20 parts decalcifying solution to 1 part tissue by volume)

What are the three methods to determine the end point for decalcification?

Radiographic, tactile, and chemical endpoints.

After decalcification, what are the next three steps to tissue processing?

Dehydration, clearing, and infiltration.

What is dehydration? What is the dehydrating agent?

Dehydration removes water from tissue; the dehydrating agents are alcohols.

What is clearing? What is the volume of clearing agent?

Clearing removes alcohol and make tissues translucent by replacing it with a substance miscible with both alcohol and paraffin wax, allowing for infiltration; 20 times the volume of the specimen.

What is the most common clearing agent?

Xylene.

What are the other names of clearing agent that can be used?

Toluene and benzene.

What is infiltration?

The process of replacing clearing agents with a medium like paraffin.

What is paraffin wax and what is the melting point?

Paraffin wax is a common embedding medium with a melting point 55-58 °C.

What is paraplast?

It is a refined paraffin wax that has been blended with plastic polymers (resins) to improve its performance for tissue embedding and sectioning.

What is an automatic tissue processor? What are the advantages of the automatic tissue processor?

An automatic tissue processor is a lab device that automates the process of preparing tissue samples for microscopic examination by moving them between various reagent baths, such as alcohol, xylene, and paraffin wax; advantages include consistency and efficiency.

Go over the maintenance of the automatic tissue processor.

Regular cleaning, checking for clogs, and ensuring proper solution levels.

What is embedding?

The process of surrounding tissue specimens in a medium for sectioning.

During the embedding procedure, the mold is placed on the __ portion of the embedding center?

Cooling portion.

What is microtomy? What is the size it sections the tissues?

the process of cutting very thin sections of tissue that have been embedded in paraffin wax (or other media), using an instrument called a microtome. Between 3 to 5 micrometers (µm)

What temperature is the tissue section placed in the water bath?

Typically at 37°C.

Where is it dried?

On a warm plate or in an oven.

Does the knife move up and down or does the tissue block move up and down?

The tissue block moves up and down.

Go over frozen sectioning -cryostat.

Frozen sectioning uses a cryostat to cut frozen tissue for rapid diagnosis.

We file the tissue blocks for a minimum of how many years?

A minimum of 20 years.

Which stain do we use?

Hematoxylin and eosin (H&E) stain.

What is regressive staining? What is progressive method?

Regressive staining: is a technique where tissue sections are intentionally overstained with dye, then selectively destained (or “decolorized”) to remove excess stain, leaving only the desired structures stained.

Progressive staining: is a technique where tissue sections are stained for a precise amount of time to achieve the desired staining intensity without the need for destaining.

The hematoxylin stains what and what color?

Hematoxylin stains nuclei blue.

What about Eosin?

Eosin stains the cytoplasm pink.

What is the pH of the bluing agent?

Usually around pH 8.0.

Go over the staining steps to familiarize with it.

deparaffinization (removes paraffin wax from tissue sections),

rehydration (remove xylene and gradually rehydrate tissue)

Staining with Hematoxylin (stain nuclei and other basophilic structures)

differentiation (if regressive method: remove excess hematoxylin to improve contrast.)

bluing (convert hematoxylin to its blue, stable form)

Counterstaining with Eosin (stain cytoplasm, collagen, and other eosinophilic structures)

Dehydration (remove water from tissue to prepare for mounting)

Clearing (replace alcohol with a medium compatible with mounting medium)

Mounting (Protect the stained tissue section with a coverslip)

Why do we cover slip?

To protect the tissue section and facilitate viewing under a microscope.

What is mounting media? Name some mounting media.

Mounting media preserves specimens; examples include Canada balsam and aqueous media.

Resin mounting media are soluble in - can be dissolved in ?

Soluble in organic solvents - can be dissolved in xylene.