Modules 11-17

Question 1

9 steps that occur in the histopathological technique

Answer 1

Gross cutting
Fixation
Dehydration
Clearing
Infiltration
Embedding
Sectioning
Staining
Microscopic examination

Question 2

4 main categories for instrument QC in the histopathology lab

Answer 2

Lubrication
Temperature
Cleaning
Maintenance

Question 3

Biopsy

Answer 3

The removal of a small piece of living tissue from an organ or other part of the body for microscopic examination to confirm or establish a diagnosis, estimate prognosis, or follow the course of a disease

Question 4

Curettage

Answer 4

Scraping of material from a cavity wall or other surface to obtain tissue for microscopic examination or remove tumor or other abnormal tissue

Question 5

6 major sections of the pathway of a surgical specimen

Answer 5

Accessioning, processing, pathologist (gross + slides), additional requirements, reports, filing

Question 6

Maximum size of tissue that can be processed in a cassette

Answer 6

2 x 3 x 0.3 cm

Question 7

Fixative

Answer 7

A substance that alters tissue through the stabilization of protein, so that it is resistant to changes in subsequent treatments of the tissue

Question 8

Preservative

Answer 8

A preservative will not swell, shrink or distort tissues, but it does not alter the tissue structure and therefore will not protect it from changes in subsequent treatments of the tissue

Question 9

Autolysis

Answer 9

The breakdown of tissues by enzymes in the tissues that continue their metabolic actions once tissues are removed from the body

Question 10

Putrefaction

Answer 10

The breakdown of tissues by bacterial action

Question 11

7 functions of a fixative

Answer 11

Prevent autolysis
Prevent putrefaction
Stabilize tissue structure
Lessen shrinkage and distortion of tissue on subsequent processing
Change the refractive index of tissue
Enhance staining
Make tissue firmer

Question 12

Additive fixative

Answer 12

Adds on to or chemically links to the tissue, changing the tissue by its addition

Question 13

Nonadditive fixative

Answer 13

React with the tissue, but do not add onto or combine with the tissue in order to act on it

Question 14

Coagulant fixative

Answer 14

Produce aggregation of protein molecules, granulation and precipitation
Result is the production of a meshwork through which other solutions can easily penetrate

Question 15

Non-coagulant fixative

Answer 15

Form addition compounds with proteins

Question 16

6 factors that affect fixation

Answer 16

Time, temperature, size, volume of fixative to tissue volume, pH, storage osmolality

Question 17

What temperature can be used to speed fixation without significantly affecting the tissue?

Answer 17

45C

Question 18

The optimal thickness for a tissue to be routinely processed

Answer 18

Less than 3mm

Question 19

The optimal amount of fixative to be used in relation to the volume of tissue

Answer 19

15-20x the volume of the tissue

Question 20

2 ways to transport unfixed tissue

Answer 20

Place biopsy on a piece of gauze dampened with saline, in a sealed container transported on ice. Or, place in container of Michel transport solution

Question 21

2 storage fluids that may be used

Answer 21

Neutral buffered formalin or 70% alcohol

Question 22

When should tissue be transferred to 70% ethanol?

Answer 22

When fixative other than formalin was used or if immunohistochemical studies are likely

Question 23

When is no fixation of a specimen required?

Answer 23

Immunofluorescence, enzymes, some immunohistochemistry studies, and most methods using frozen sections

Question 24

Postfixation

Answer 24

When a tissue which is already fixed, is fixed again, using another fixing agent that would enhance its staining properties

Question 25

2 reagents that may be used to “postfix” a tissue

Answer 25

Bouin’s or osmium tetroxide

Question 26

Is formalin a coagulating or noncoagulating fixative?

Answer 26

Noncoagulating

Question 27

The pH ranges at which formalin may be used

Answer 27

pH 7-7.5 or pH 8-9

Question 28

Advantages of using formalin as a fixative

Answer 28

Penetration rate is fast
Less shrinkage of tissue
Hardening of tissue
Inexpensive
Solutions are stable
Many routine, special, and histochemical staining methods may be performed after formalin fixation
After fixation, tissues may be processed in paraffin, celloidin, plastics, or used for frozen sections

Question 29

Disadvantages of using formalin as a fixative

Answer 29

Rate of fixation is slow
May cause dermatitis
Unbuffered formalin in solutions can produce precipitates in tissue
Concentrated formaldehyde can polymerize forming paraformaldehyde, reducing the working strength of the formaldehyde solution

Question 30

When will formalin precipitate form?

Answer 30

If the formalin solution becomes acidic

Question 31

Solution used to remove formalin precipitate

Answer 31

Alcoholic picric acid or 2% ammonia in 80% alcohol

Question 32

Is mercuric chloride a coagulating or noncoagulating fixative?

Answer 32

Coagulating

Question 33

Which fixative causes a diffuse PAS reaction in tissues?

Answer 33

Glutaraldehyde

Question 34

What is the best dehydrant?

Answer 34

Ethanol

Question 35

What is the best substitute for ethanol as a dehydrant?

Answer 35

Isopropanol

Question 36

Universal solvent

Answer 36

A solution that performs both dehydration and clearing steps of processing. eg. dioxane, tertiary butanol and tetrahydrofuran

Question 37

Result of leaving tissue in dehydrating alcohols or clearing agents for extended periods of time

Answer 37

Tissue will be hard, shrunken, and difficult to section. Nothing can be done to fix this issue.

Question 38

Infiltration

Answer 38

The use of a support media that will permeate all the tissue spaces and maintain the structural integrity of the tissue

Question 39

Most commonly used infiltrant

Answer 39

Paraffin wax

Question 40

Disadvantages of using a rotary tissue processor

Answer 40

Slow, fumes, carryover

Question 41

The most common type of microtome in use in histopathology labs

Answer 41

Rotary microtome

Question 42

Freeze-drying

Answer 42

Instantaneous freezing of tissues which stops all vital processed

Question 43

3 steps in the freeze-drying technique

Answer 43

Quenching, drying, sectioning