basic histologic techniques Flashcards Preview

► Med Misc 05 > basic histologic techniques > Flashcards

Flashcards in basic histologic techniques Deck (67):
1

12 Steps of Histologic Techniques

numbering
receiving of specimens
fixation
dehydration
clearing
infiltration
embedding
blocking and trimming
sectioning
staining
mounting
labelling

2

first and most important step
logging in a log book the details of the tissue

numbering

3

tissue specimens should be properly labeled and with a corresponding request
tissue s will be described by the pathologist (gross description)
tissues will be cut by the pathologist

receiving of specimens

4

tissues are immersed in a fixative to prevent decomposition and preserve structure

fixation

5

removal of excess water using ascending grades of alcohol

dehydration

6

removal of excess alcohol
makes tissues clear/transparent
prepares tissues for paraffin impregnation

clearing/dealcoholization

7

tissue cavities are saturated w/ paraffin wax

infiltration

8

impregnated tissue is oriented and embedded in paraffin block to form a tissue block

embedding

9

separation of embedded tissues into blocks
removal of excess paraffin wax using knives

blocking and trimming

10

very thin sections of tissue are cut using microtome

sectioning

11

using H& E (routine stain)

staining

12

stained tissue sections on a slide are added w/ mounting medium and covered w/ coverslip

mounting

13

Responsible for transcribing the dictations of the pathologist

Medical technologist

14

Used in labeling slecimens

Pencil

15

Provides the gross description
Cuts of sections the specimen when received

Pathologist

16

Technique done to kill microorganism in the specimen

Fixation

17

Routinely used fixative

Formalin (10%) or formaldehyde

18

Stock solution of formalin that must be diluted

37% formalin

19

Agent used in dehydration

Increasing grades of Ethanol or ethyl alcohol

20

Effect of clearing to tissues

Tissues become translucent or transparent

21

Most common clearing agent

Xylol or xylene

22

Melting point of paraffin wax

56-57C

23

Ways of performing infiltration

Manual
Using automatic tissue processor

24

Another name for infiltration

Impregnation

25

Performs fixation to infiltration (steps 2-5)
Has a basket wherein tissue cassette will be placed

Automatic tissue processor

26

How long do cutting to infiltration take?

1 day

27

The act of placing impregnated tissue in the embedding mold

Orientation

28

Examples of embedding mold

Paper boat
Plastic mold
Ice cube tray

29

Separation of embedded tissues into blocks
Separating small block from big block

Blocking

30

Removal of excess paraffin wax using knives until a truncated pyramid is made

Trimming

31

Thickness required when sectioninf

4-6 nm

32

Where tissue section is placed before in the microtome
Surface is colored black
Removes wrinkles

Flotation Water bath

33

After flotation, perform ____

Fishing

34

Act of scooping the tissue from the flotation water bath

Fishing out

35

Another term for staining

Coloring

36

A nuclear stain
Color is blue or dark blue

Hematoxylin

37

A cytoplasmic stain
Reddish or pinkish

Eosin

38

Also serves as a counterstajn

Eosin

39

Provides contrast and background

Eosin

40

2 types of mounting medium

Aqueous
Resinous

41

Primary mounting medium used in histology

Resinous

42

Ex of aqueous mounting medium

Water

43

Example of resinous mounting medium

Eukitt and Canada balsam

44

final step in tissue preparation

labeling

45

Final step
Use of gum labels
May be computerized or bar coded

Labelling

46

– fixative often used for EM; reinforces fixation by being a dialdehyde capable also of cross-linking proteins

• Gluteraldehyde

47

– preserves and stains membrane lipids and proteins

Osmium tetroxide

48

In electron microscopy, a _____ procedure is done.

double-fixation

49

basic histologic technique
• ethanol is then replaced by an organic solvent miscible with both alcohol and embedding medium
• Alcohol is removed in toluene or other agents in which both alcohol and paraffin are miscible

3. Clearing

50


• Fully cleared tissue is placed in melted paraffin in an oven at 52 – 60C
• At 52 – 60C, clearing solvent evaporates and tissue is filled with paraffin wax

4. Infiltration

51

• The paraffin-infiltrated tissue is placed in a small mold with melted paraffin and allowed to harden
• Impregnated tissue hardens in a small container of paraffin at RT

Embedding

52

SPATIAL UNITS in Histology:

micrometer, nanometer, angstrom

53

– cell components with a net negative charge (anionic) stain readily with basic dyes (eg. Nucleic acids)
-have acids in their composition

• Basophilic

54

- cell components that are cationic have affinity for acidic dyes (eg. Proteins with many ionized amino groups)

• Acidophilic

55

– toluidine blue, alcian blue, methylene blue, hematoxylin

• Basic Dyes

56

– eosin, orange G, acid fuchsin

• Acid dyes

57

type of stain
– used in more complex histologic procedures
-help to distinguish extracellular tissue components better than H&E


• Trichrome (Mallory stain, Masson stain)

58

chromatin with active dna
stains lightly

euchromatin

59

inactive dna
stains darkly

heterochromatin

60

euchromatin that becomes a heterochromatin

facultative heterochromatin

61

whole process of an X chromosome becoming a barr body or sex chromatin

lyonization

62

according to lyon's hypothesis, at the _____ cell stage, one of the X in the female gets turned off

100

63

specimen used for determining sex chromatin

peripheral blood (neutrophil)
tongue and buccal cavity

64

first blood must be wiped off as it contains

tissue juices

65

methanol number of seconds

5 seconds, air dry

66

eosin number of seconds

3

67

methylene blue number of seconds

6 seconds

Decks in ► Med Misc 05 Class (295):