Things to go over for the final module exam (Lesson Content 1,2,3,4)(70 marks marks consisting of MCQ, T/F, Match)

What is histology?

Histology is the study of the microscopic structure of tissues.

What is histopathology?

Histopathology is the examination of tissues for disease.

What is the first step in the tissue processing stages?

The first step is fixation.

What fixative is typically used to fix tissue?

Formalin is commonly used to fix tissue.

How do you prepare 4% formaldehyde solution?

To prepare 4% formaldehyde, dilute 10% formalin with water.

What concentration of formalin is used to fix tissue?

A 10% concentration of formalin is used for fixation.

How long should tissue be fixed?

Tissue should be fixed for a duration depending on the tissue size, typically 24-48 hours.

What is the ratio of fixation to tissue volume?

The typical ratio is 10:1, fixative to tissue volume.

What factors affect tissue after processing?

Factors include the type of tissue, fixation time, and fixative used.

How does a tissue capsule affect the fixation process?

A capsule can impede penetration of the fixative, leading to incomplete fixation.

What is the rate at which tissue is fixed?

The tissue is fixed at a rate of approximately 1 mm per hour.

What is the primary aim of a fixative?

The primary aim is to preserve tissue structure and composition.

What is Zenkers and Helly fluid?

Zenkers fluid is a fixative made of mercuric chloride, potassium dichromate, and formalin; Helly's fluid contains formalin.

What is grossing in histology?

Grossing is the step of preparing and describing the tissue specimen before fixation.

When is the grossing step performed?

Grossing is performed before fixing the tissue.

Who performs the gross description of the tissue?

This task is typically performed by a pathologist or histotechnologist.

What is the typical size a tissue is cut for grossing?

Tissues are usually cut into small pieces about 2-4 cm in size.

What size of tissue is placed in a cassette?

Typically, small pieces or sections that can fit into the cassette.

What size of tissue is placed in a basket?

Larger or bulkier specimens that do not fit in cassettes.

What is decalcification?

Decalcification is the process of removing calcium to allow for better tissue processing.

What agents are used for decalcification?

Common agents include EDTA or hydrochloric acid.

Do we always perform decalcification?

Decalcification is only performed on calcified tissues if necessary.

When is decalcification performed?

Decalcification is performed after fixation.

What is dehydration in tissue processing?

Dehydration involves removing water from the tissue using increasing concentrations of alcohol.

What is the clearing step in tissue processing?

Clearing involves replacing alcohol with a clearing agent like xylene.

What is the melting point of paraplast?

Paraplast has a melting point of approximately 56-58 degrees Celsius.

What color crystals indicate water in the paraffin during impregnation?

The presence of white, waxy crystals indicates water contamination.

What happens to the slide after it is dried in the oven?

the slide's tissue section will be firmly adhered to the glass, allowing for subsequent staining and analysis.

What happens if tissue is over-dehydrated?

Over-dehydration can lead to tissue brittleness and poor quality sections.

What does an embedding center contain?

An embedding center contains tools and materials for embedding tissue in paraffin.

What is an automated tissue processor?

An automated tissue processor is a machine that automates the tissue processing steps.

What is the principle of automated tissue processors?

Fluid exchange and consistent timing for each processing step.

systematically transfer fixed tissue samples through a series of reagents to remove water (dehydration), replace it with a clearing agent (clearing), and then infiltrate it with paraffin wax (infiltration). This makes tissues firm enough to be sliced into thin sections for microscopic analysis.

Can the automated tissue processor be left unattended overnight?

No. It is not advisable to leave it running without supervision.

How many stations does an automatic tissue processor have?

It usually has 10-12 stations.

What are the stages in the H&E staining procedure?

The stages include fixation, dehydration, clearing, staining with hematoxylin, bluing, and counterstaining with eosin.

What color does hematoxylin stain nuclei?

Nuclei and basophilic components are stained blue or purple.

What colors do collagen and muscle cells stain in H&E?

Collagen stains pink, and muscle cells stain pink as well.

What agent is used for dehydration after H&E staining?

Ethanol is used as the dehydration agent.

What is the purpose of a bluing agent?

The bluing agent neutralizes excess acidity after hematoxylin staining.

What is Scott's tap water?

Scott's tap water is a buffered solution used to promote bluing.

What is the difference between progressive and regressive H&E staining?

Progressive staining uses longer hematoxylin exposure; regressive staining involves differentiation.

What is the most important step in regressive H&E stain?

The differentiation step with acid-alcohol.

What percentage of acid-alcohol is used for differentiation?

Usually, 1-2% acid-alcohol is used.

What is Romanovsky stain?

Romanovsky stain is a type of stain used to visualize blood cells and parasites.

What are the ingredients of Romanovsky stain?

Ingredients typically include eosin and methylene blue.

What is the mounting media?

The mounting media is the fluid used to cover histological slides.

Which mounting media do we use?

xylene

How do we remove excess mounting media on the slide?

Excess media is wiped away gently from the edges of the slide.

How long do we keep histology tissue blocks in filing?

Tissue blocks are usually kept in filing for 10-20 years

What is a cryostat?

A cryostat is a device used to cut thin sections of frozen tissue.

Can we process STAT specimens on a cryostat?

Yes, STAT specimens can be processed quickly on a cryostat.

What is cytology?

Cytology is the study of individual cells.

What stain is used for pap smears?

Papanicolaou stain is commonly used for pap smears.

What are the methods for Papanicolaou stain?

There are regressive and progressive Papanicolaou staining methods.

What is the ThinPrep system method?

ThinPrep is a method for preparing liquid-based cytology samples.

What is the Surepath system?

Surepath is another liquid-based cytology preparation system.

What is the difference between gyn and non-gyn specimens?

Gyn specimens relate to female reproductive cells; non-gyn specimens are from other tissues.

What is a cytospin?

A cytospin is a centrifugation method to concentrate cells onto a slide.

What is sediment and supernatant?

Sediment refers to the solid material at the bottom after centrifugation; supernatant is the liquid above.

What is a direct smear?

A direct smear is the application of a specimen directly onto a slide.

What is pick and smear?

Pick and smear is a method for preparing smears from solid specimens.

How does a patient collect a sputum specimen?

Patients typically expectorate sputum directly into a sterile container.

What fixative is used for smears made of sputum?

95% ethanol

What is the standard fixative for cytology?

The standard fixative is usually 95% ethanol.