MLGH 106- Introduction to Histology and Cytology -Lesson 1 Q&A Flashcards

100 practice flashcards covering core histology and cytology concepts from the provided notes.

Anatomic Pathology includes

Pathology (the study of disease – usually cancer), Cytopathology (diagnosis based on characteristics of cells), Histopathology (examination of tissues).

Foundation of histology and cytology labs

Assessment of morphologic features of cells or tissues.

Cytopathology

Diagnosis based on characteristics of cells.

Histopathology

Examination of pieces of tissue.

Cytology and Histology labs relationship

Normally separated, but have many similarities.

Histotechnologist role

Helps prepare samples for the pathologist to examine.

Key specimen prep steps by histology staff

Accessioning, staining, cover slipping, filing.

Final slide thickness in histology

3-5 μm thick.

Anatomic Pathology specimen types

Surgical specimens, autopsy specimens, biopsies.

FFPE block

Formalin-fixed paraffin-embedded tissue block.

10% neutral buffered formalin

Universal fixative; ~3.7-4% formaldehyde in neutral pH.

H&E staining purpose

Hematoxylin and Eosin stain used for routine histology.

Tissue processing steps

Fixation, dehydration, clearing, wax infiltration, embedding, trimming, sectioning.

Slide tissue thickness

3-5 μm.

Ischemic time

Time from tissue removal to placement in fixative.

Fixative to tissue volume ratio

Typically 15-20:1.

Fixation rate

Tissue fixed at about 1 mm per hour.

Chemical vs physical fixation

Chemical uses fixative solution; Physical includes heating, microwaving, cryo-preservation.

Specimen reception requirement

Specimens must be received with a requisition.

Surgical number

Sequential specimen identifier carried through all procedures.

Accession log purpose

Daily log recording surgical numbers.

Requisition information fields

Patient name, date, tissue type, site, physician location.

Specimen accessioning purpose

To track the specimen through all procedures and into the report.

Specimen rejection reasons

Labeling errors; missing/incorrect requisition; wrong fixative; insufficient fixative; no fixative; leaking containers; container too small.

Priority level – Emergency Department

Immediate results (NOW).

Priority level – STAT

Turnaround time 1 hour.

Priority level – ASAP

Turnaround time 4 hours.

Priority level – Routine

Turnaround time about 24 hours.

Fresh specimen transport

Must be delivered promptly; refrigeration; do not freeze.

Fixed specimen transport

Less critical regarding temperature control.

TDG packaging requirements

Rigid, leak-proof container; absorbent; leak-proof secondary container; outer container.

Dry ice packaging rule

Do not seal dry ice in the sealed secondary container; place between inner container and outer bag.

Specimen rejection policy contents

Who can submit; minimum volumes; suitable containers; properly filled requisition; properly labeled; broken slides; leaking specimens.

Fixation definition

Process to preserve tissue by stopping life functions and stabilizing structure.

First step in tissue processing

Fixation.

Specimen storage before fixation

Non-fixed specimens should be placed in fixative and stored at 4°C.

Ischemic time importance

Long ischemia increases autolysis; fix promptly.

Fixative volume for penetration

Fixative volume should be 15-20 times tissue volume.

Fixation pH for electron microscopy

Buffered to pH 7.2-7.4.

Fixative choice considerations

What structures to demonstrate and long-term tissue preservation.

Fixation artifacts

Formalin pigment; Mercury pigment; Chrome pigment.

Formalin pigment removal

Treat with alcoholic picric acid or alkaline alcohol.

Fixative classification – additive vs non-additive

Additive fixatives actively participate in denaturing proteins vs non-additive ones.

Fixative classification – coagulant vs non-coagulant

Coagulant fixatives produce heavy precipitates and shrinkage; non-coagulants produce light precipitates with less shrinkage.

Fixative classification – tolerant vs intolerant

How long tissue can stay in fixative without damage.

Primary fixing agents

Examples include Formaldehyde, Glutaraldehyde, Mercuric Chloride, Ethanol, Picric acid, Acetic acid, Osmium tetroxide, Glutaraldehyde.

Formalin as a fixative

10% neutral buffered formalin (NBF); widely used; 3.7-4% formaldehyde; neutral pH.

Formalin concentration in 10% NBF

About 3.7-4% formaldehyde.

Advantages of formalin

Good penetration; tolerant; cheap; useful for nervous system; does not cause excessive hardening.

Disadvantages of formalin

Irritating; carcinogenic; fumes; dermatitis; requires fume hood.

Formalin pigment (acid hematin)

Formalin pigment forms when fixative is too acidic; removal via alcoholic picric acid or alkaline alcohol.

Paraformaldehyde formation

Formalin can polymerize to paraformaldehyde; filtering removes polymerized form.

10% Neutral Buffered Formalin preparation components

Distilled water; buffers (NaH2PO4, Na2HPO4); Formalin.

Formalin safety measures

Ventilation; gloves; fume hood to minimize fumes.

Compatibility with electron microscopy

Fixative pH and choice affect EM preservation and ultrastructure.

Zenker's fluid

Fixative containing mercuric chloride and acetic acid; highly toxic; good staining but metal corrosion risk.

Bouin's fluid

Fixative with picric acid; rapid penetration; glycogen demonstration; explosive and hardening issues.

Brasil's alcoholic picro-formal fixative

Best fixative for glycogen; shares disadvantages of Bouin.

Common reagents handling guidance

Do not memorize recipes; refer to procedures; respect SDS; label and store properly; use distilled water unless stated.

H&E staining summary

Hematoxylin stains nuclei blue; Eosin stains cytoplasm pink.

Rotary microtome function

Cuts paraffin blocks into thin sections for mounting on slides.

Paraffin section thickness

Approximately 3-5 μm (standard).

Slide staining steps (overview)

Deparaffinize, rehydrate, stain with H&E, mount coverslip.

Requisition fields (examples)

Patient name; date; tissue type; site; physician/location.

Surgical numbering details

Year, specimen number, unique identifier; used on requisition, container, cassettes, slides, and report.

Specimen labeling requirements

Clear labeling; consistent with SOP; ensure correct requisition.

Sharps handling in histology

Proper disposal in sharps container; avoid injury.

WHMIS

Workplace Hazardous Materials Information System; labeling, dates, storage and disposal of hazardous solutions.

PPE in histology labs

Appropriate personal protective equipment (gloves, lab coat, eye protection).

Spill containment in histology

Procedures to contain and clean spills of hazardous materials.

Incident documentation

Document safety incidents and injuries for follow-up.

Ergonomics in histology

Apply proper ergonomic principles to prevent injuries.

Fresh specimen transport temperature

Deliver quickly; refrigeration; do not freeze.

Fixed specimen transport temperature

Less critical regarding temperature control.

Cover slipping purpose

Protects the stained specimen and preserves it.

IHC-grade paraffin blocks

Paraffin blocks prepared for immunohistochemistry.

Embedding step in Tissue Processing

Infiltration of tissue with paraffin after clearing.

Specimen orientation in embedding

Proper orientation ensures correct histologic view.

SOP and quality control

Standard Operating Procedures and quality checks ensure consistency.

Pathologist's report linkage

Specimen numbers used to link requisition to pathologist's report.

Glycogen demonstration sensitivity

Bouin's and Brasil's fixatives highlight glycogen.

Glutaraldehyde

Primary fixing agent used particularly for electron microscopy.

Mercuric chloride safety

Toxic; avoid exposure; ensure thorough washing.

Acetic acid use in fixatives

Part of Zenker's fixative; enhances nuclear detail.

Formalin hazards and ventilation

Ventilation and fume hood essential; formaldehyde irritant and potential carcinogen.

Formalin polymerization

Formalin can polymerize to paraformaldehyde; filter to remove.

Commercial fixatives for glycogen demonstration

Bouin's, Brasil's fixatives.

H&E as universal stain

Most widely used stain for routine histology.

EM compatibility considerations

EM requires specific fixatives and pH control for ultrastructure.

Specimen accessioning data fields

Requisition ID; patient demographics; sample source.

Stain validation

Controls and procedural validation ensure staining accuracy.

Paraffin block handling

Handle blocks carefully; store properly to prevent damage.

Slide labeling after staining

Slides must be labeled with patient and specimen data.

Specimen turn-around-time tracking

TAT tracked from receipt to results.

Quality control in histology

Regular checks at fixation, processing, embedding, staining to ensure consistency.

Clinical relevance of fixation

Accurate fixation is essential for diagnostic quality slides.

SDS importance

Safety Data Sheet – hazard information for reagents.

SDS usage

Refer to SDS for safe handling and emergency measures.

Dangers of working with formaldehyde

Irritant and potential carcinogen; require fume hood and ventilation.

Preventing formalin pigment

Maintain neutral pH and proper handling to avoid pigment formation.