Introduction to Histology and Cytology -Lesson 1 Vocab Flashcards

Vocabulary flashcards covering key histology and cytology concepts from the lecture notes.

Anatomic Pathology

The branch of pathology that involves the laboratory examination of tissue samples from the body for diagnostic purposes.

Cytopathology

Diagnosis based on characteristics of cells; analysis focuses on cells rather than whole tissues.

Histopathology (Histology)

The study of diseased tissues under the microscope; examination of tissue sections to diagnose disease.

Morphologic features

Structural characteristics of cells or tissues used to assess disease.

Glass slide

A flat glass surface on which stained tissue/cells are mounted for microscopic examination.

Pathologist

Medical doctor who interprets histology slides and makes diagnostic conclusions.

Medical laboratory technician

Lab staff who prepare specimens, stain, cover-slip, and file.

Accessioning

Receiving, labeling, and assigning a unique accession number to specimens.

Specimen

Biological material (tissue, cells) collected for testing.

Requisition

Form accompanying a specimen detailing patient information and tissue type.

PPE (Personal Protective Equipment)

Protective gear used to prevent exposure to hazards (gloves, gown, goggles).

WHMIS

Workplace Hazardous Materials Information System; safety labeling and data for hazards.

Sharps

Items capable of puncturing skin (needles, scalpels) requiring safe disposal.

Spill containment

Procedures to control and clean hazardous material spills.

Laboratory safety devices

Safety features like eyewash stations and safety showers used in labs.

Ergonomics in histology

Principles to prevent injury through proper workstation design and posture.

Histology department

Lab section that processes tissue samples for microscopic analysis.

Histotechnologist

Technologist who prepares samples (fixation, embedding, staining) for pathologists.

Special stains

Stains used to highlight specific cell components beyond routine H&E.

Surgical specimen

Tissue obtained from surgery for microscopic examination.

Autopsy specimen

Tissue obtained during autopsy for diagnosis or teaching.

Biopsy

Excision of a small tissue sample for diagnosis.

Amputation specimen

Tissue removed during amputation used for diagnosis.

Large partial organ

Partial organ specimen submitted for analysis.

FFPE

Formalin-fixed paraffin-embedded; tissue preserved and embedded for sectioning.

Fixation

Process of preserving tissue by halting biological activity and stabilizing structure.

Dehydration

Removal of water from tissue using alcohol.

Clearing

Replacing dehydrant with a solvent (e.g., xylene) to prepare for embedding.

Infiltration

Penetration of tissue with embedding medium (paraffin).

Embedding

Incorporation of tissue into paraffin to form blocks for sectioning.

Sectioning

Cutting thin tissue slices (typically 3–5 μm) from paraffin blocks.

Paraffin

Wax used to embed tissue during histology.

FFPE block

A paraffin block containing formalin-fixed tissue for sectioning.

H&E

Hematoxylin and eosin stain; standard histology stain.

Fixative

Chemical solution used to preserve tissue by fixing its structure.

Formalin

A solution of formaldehyde in water; common fixative.

10% Neutral Buffered Formalin (NBF)

Standard fixative; 3.7–4% formaldehyde; buffered to neutral pH.

Ischemic time

Time from tissue removal to placement in fixative; shorter is better.

Fixative volume ratio

Fixative volume should be 15–20 times the tissue volume for proper penetration.

Chemical fixation

Preservation by chemical agents that denature proteins.

Physical fixation

Fixation by physical means such as heating or microwaving.

Microwave fixation

Rapid, microwave-assisted fixation of tissue.

Temperature effect on fixation

Higher temperatures increase fixation rate; common range includes 0–4°C historically and room temperature in practice.

pH of fixative

pH affects preservation; buffered around 7.2–7.4 for certain applications.

Tissue size

Larger tissues fix more slowly due to slower fixative penetration.

Immersion fixation

Submerging tissue in fixative for preservation.

Perfusion fixation

Fixation by circulating fixative through tissue via vessels.

Formalin pigment

Acid hematin pigment formed when formalin becomes too acidic; removed with alcoholic picric acid.

Mercury pigment

Dark pigment caused by mercury in fixatives; removed with alcoholic iodine and sodium thiosulfate.

Chrome pigment

Pigment related to chromium; removed by running tap water.

Zenker's fluid

Fixative containing mercuric chloride; excellent nuclear/cytoplasmic staining but highly toxic.

Bouin's fluid

Fixative containing picric acid; good for glycogen demonstration but explosive hazards.

Brasil's alcoholic picro-form fixative

Routine fixative for surgical specimens; glycogen demonstration; contains picric acid.

Picric acid

Explosive fixative component used in Bouin’s and Brasil’s fixatives; hazardous.

Osmium tetroxide

Fixative for lipids and electron microscopy; highly toxic.

Glutaraldehyde

Crosslinking fixative used for ultrastructural preservation.

Ethanol

Alcohol fixative; primary fixing agent in some protocols.

Acetic acid

Acidic component of some fixatives.

Potassium dichromate

Chromium-containing fixative component.

Formaldehyde

Gas used to fix tissues; commonly converted to formalin for solution.

Paraformaldehyde

Polymerized form of formaldehyde used in some fixatives.

Fixative safety

Handling requires PPE, ventilation, and proper procedures due to hazards.

Fume hood

Ventilated cabinet to remove hazardous fumes (e.g., formaldehyde).

Carcinogenic nature of formaldehyde

Formaldehyde is a known carcinogen; handle in a fume hood.

Autolysis

Self-digestion of cells by endogenous enzymes after death.

Putrefaction

Decomposition of tissue by bacterial activity after death.

Denaturation of proteins

Fixatives alter proteins by breaking their structured state.

Gel formation

Hardening of tissue into a gel-like state during fixation.

Fixed specimen

Specimen that has been preserved by fixation.

Unfixed specimen

Specimen not yet fixed; vulnerable to degradation.

4°C storage

Refrigeration to slow degradation of non-fixed tissues.

Tissue processing

Sequence: fixation, dehydration, clearing, infiltration, embedding before embedding.

Rotary microtome

Instrument that cuts thin sections from paraffin-embedded tissue blocks.

Paraffin sections

Thin tissue slices cut from paraffin blocks for mounting on slides.

H&E staining

Routine stain; hematoxylin colors nuclei blue; eosin colors cytoplasm pink.

Requisition information

Details required on requisition: patient name, date, tissue type, site, location.

Surgical number

Unique surgical identifier assigned to a specimen.

Accession log

Daily log recording specimens and their accession numbers.

Specimen rejection policy

Written policy outlining submission rules, minimum volumes, container types, and requisitions.

Labeling

Proper labeling of specimens and requisitions is required.

Incomplete requisition

Missing information; grounds for specimen rejection.

Incorrect fixative

Using the wrong fixative leads to specimen rejection.

No fixative

Specimens arriving unfixed can be rejected.

Leaking containers

Leaking containers lead to specimen rejection for safety and integrity.

Small container

Container too small for the specimen; rejection.

Priority specimen

Specimens designated with higher urgency (emergency, STAT, ASAP, routine).

Emergency Department immediate

NOW priority; emergency results required immediately.

STAT

Turnaround time of 1 hour for urgent specimens.

ASAP

Turnaround time of approximately 4 hours for urgent specimens.

Routine

Turnaround time of about 24 hours for standard specimens.

TDG packaging

Packaging requirements for transporting dangerous goods.

Rigid leak-proof container

Primary, leak-proof container for specimen transport.

Absorbent material

Material inside packaging to absorb potential leaks.

Secondary leak-proof container

Leak-proof secondary container to prevent leaks during transport.

Outer container

Exterior packaging protecting internal containers.

Dry ice packaging

When using dry ice, do not seal the secondary container; place dry ice between containers.

Fixed specimen handling

Procedures for handling specimens that have been fixed.

Unfixed specimen handling

Procedures for handling specimens not yet fixed.

Reagent handling

Safe handling and use of common histology reagents.

SDS (Safety Data Sheets)

Documents detailing hazards and handling of chemicals.