Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histopathology Laboratory > Infiltration and Embedding > Flashcards

Infiltration and Embedding Flashcards

1
Q

the process whereby the clearing agent is completely removed from the tissue and replaced by a medium that will completely fill all the tissue cavities and give a firm consistency to the specimen

A

Infiltration/ Impregnation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

the process by which the impregnated tissue is placed into a precisely arranged position in a mold containing a medium which is then allowed to solidify.

A

Embedding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 types of infiltration and embedding medium?

A
  1. Paraffin wax
  2. Celloidin (collodion)
  3. Gelatin
  4. Plastic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  • simplest, most common, and best embedding medium used for routine tissue processing
  • a polycrystalline mixture of solid hydrocarbons produced during the refining of coal and mineral oils
  • solid at room temperature but melts at temperatures up to about 65°C or 70°C
A

Paraffin wax

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

the most common melting point at different temperatures for histological use of paraffin wax

A

56°C - 58°C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The traditional advice with paraffin wax

A

use about 2°C above its melting point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

To decrease viscosity and improve infiltration of the tissue, technologists often increase the temperature to

A

60°C or 65°C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Paraffin wax is traditionally marketed by its melting points which range from

A

39°C to 68°C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when the paraffin was overheated?

A

brittle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens if prolonged impregnation of paraffin wax?

A

tissue shrinkage and hardening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Tissues become soft and shrunken, and tissue blocks crumble when sectioned and break up when floated out in a water bath.

A

Inadequate impregnation that promote retention of the clearing
agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In a laboratory with temperature ranging from 20-24°C, paraffin wax with a melting point of______ is indicated. If the laboratory temperature is between 15-18°C, the melting point of wax to be used should be between _______

A

54-58°C
50 and 54°C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

3 ways by which paraffin wax infiltration and embedding of tissues may be performed

A
  1. manual processing
  2. automatic processing
  3. vacuum embedding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

at least 4 changes of wax are required at 15-minute interval and then the specimen is immersed in another fresh solution of melted paraffin for approximately 3 hours

A

Manual Processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

One example of automatic tissue processing machine

A

Elliot Bench-Type Processor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Presence of any odor in the clearing agent during final paraffin wax bath in automatic processing indicates

A

paraffin wax needs to be changed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

the most critical stage of tissue processing

A

dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Wax bath thermostats should be set at least ______ the melting point of the wax

A

3 degrees above

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
  • involves wax impregnation under negative atmospheric pressure inside an embedding oven
  • this technique is particularly recommended for urgent biopsies, for delicate tissues such as lung, brain, connective tissues, decalcified bones, eyes, spleen, and central nervous system.
A

Vacuum Embedding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

With vacuum embedding, the time required for complete impregnation is reduced by _________ of the normal time required for tissue processing

A

25% -75%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In vacuum embedding oven, the vacuum chamber is enclosed in a thermostatically controlled water-jacket, usually maintained at a temperature of _____ the melting point of the wax

A

2-4°C above

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In vacuum embedding oven, the degree of the vacuum should not exceed

A

500 mm. Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

This is provided to prevent water from being sucked back into the trap bottle and vacuum chamber when the water or suction pump is closed

A

stopcock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Out of the 3 methods of paraffin wax impregnation, which one gives the fastest result?

A

Vacuum Impregnation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

infiltration in overheated paraffin (above 60°C) will

A

produce shrinkage and hardening of tissues and destroy lymphoid tissues completely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

To avoid shrinkage, hardening of tissues, and destroying lymphoid tissues completely due to infiltration in overheated paraffin _______

A

the paraffin oven must be maintained at a temperature 2 to 5°C above the melting point of paraffin to be used for impregnation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Example of a coarse filter paper

A

Green’s No. 904

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

When wax has been reused, some amount of water inevitably is mixed with it, how can you remove the water?

A

heating the wax to 100-105°C, thereby raising its melting point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Substitute for Paraffin wax

A
  1. Paraplast
  2. Embeddol
  3. Ester wax
  4. Water soluble waxes
  5. Dimethyl sulphoxide
30
Q
  • a mixture of highly purified paraffin and synthetic plastic polymers, with a melting point of 56-57°C.
  • more elastic and resilient than paraffin wax thereby permitting large dense tissue blocks such as bones and brain to be cut easily
A

Paraplast

31
Q
  • synthetic wax substitute similar to Paraplast with a melting point of 56-58°C.
  • less brittle and less compressible than Paraplast
A

Embeddol

32
Q

a semisynthetic wax recommended for embedding eyes

A

Bio/aid

33
Q

a product of paraffin, containing rubber, with the same property as Paraplast.

A

Tissue Mat

34
Q
  • has a lower melting point (46-48°C), but it is harder than paraffin
  • not soluble in water, soluble in 95% ethyl alcohol, hence can be used for impregnation without prior clearing of tissue
A

Ester wax

35
Q

microtome used for ester wax-impregnated tissue

A

sliding or sledge type microtome

36
Q
  • plastic polymers, mostly polyethylene glycols with melting points of 38-42°C or 45-56°C
A

Water soluble waxes

37
Q
  • a polyethylene glycol containing 18 or more carbon atoms, which appears solid at room temperature
  • It is soluble in and miscible with water; hence does not require dehydration and clearing of the tissue
  • Cytologic details are excellently preserved
A

carbowax

38
Q

Routine processing of carbowax

A

70% for 30 minutes
90% for 45 minutes
100% for 1 hour
100% for 1 hour

temperature at 56°C

39
Q

What will reduce tissue distortion and promote flattening and “floating out” of sections?

A

Adding soap to water or using 10% Polyethylene Glycol 900

40
Q
  • added to proprietary blends of plastic polymer paraffin waxes reduces infiltration times and facilitates thin sectioning
  • scavenges residual transition solvent and probably alters tissue permeability by substituting for or removing bound water thus improving infiltration.
A

Dimethyl sulphoxide (DMSO)

41
Q

Some individuals who handle DMSO-paraffin wax may experience

A

unpleasant and annoying oyster or garlic taste caused by DMSO metabolites

42
Q

is a purified form of nitrocellulose soluble in many solvents, suitable for specimens with large hollow cavities which tend to collapse, for hard and dense tissues such as bones and teeth, and for large tissue sections of the whole embryo.

A

Celloidin (Collodion)

43
Q

2 methods for celloidin impregnation

A
  1. Wet Celloidin Method
  2. Dry Celloidin Method
44
Q

celloidin method recommended for bones, teeth, large brain sections and whole organs

A

Wet Celloidin Method

45
Q

Celloidin method preferred for processing of whole eye sections

A

Dry Celloidin Method

46
Q

made up of equal parts of chloroform and cedarwood oil

A

Gilson’s mixture

47
Q

another form of celloidin soluble in equal concentration of ether and alcohol, with a lower viscosity, allowing it to be used in higher concentrations and still penetrate tissues rapidly

A

Low Viscosity Nitrocellulose (L.V.N.)

48
Q

examples of plasticizers

A

oleum ricini
castor oil

49
Q
  • rarely used except when dehydration is to be avoided and when tissues are to be subjected to histochemical and enzyme studies
  • used as an embedding medium for delicate specimens and frozen tissue sections because it prevents fragmentation of tough and friable tissues when frozen sections are cut.
  • water-soluble, and does not require dehydration and clearing
  • has a low melting point and does not cause over-hardening of tissues by heating.
A

GELATIN

50
Q

serves to prevent the growth of molds in gelatin impregnation

A

1% phenol

51
Q

The process by which a tissue is arranged in precise positions in the mold during embedding, on the microtome before cutting, and on the slide before staining

A

Orientation

52
Q

4 Types of Blocking-out Molds

A

Leuckhart’s Embedding Mold
Compound Embedding Unit
Plastic Embedding Rings and Base Mold
Disposable Embedding Molds

53
Q

an embedding mold which consists of two L-shaped strips of heavy brass or metal arranged on a flat metal plate and which can be moved to adjust the size of the mold to the size of the specimen

A

Leuckhart’s Embedding Mold

54
Q

an embedding mold that is made up of a series of interlocking plates resting on a flat metal base, forming several compartments. It has the advantage of embedding more specimens at a time, thereby reducing the time needed for blocking.

A

Compound Embedding Unit

55
Q

an embedding bold that is consist of a special stainless steel base mold fitted with a plastic embedding ring, which later serves as the block holder during cutting.

A

Plastic Embedding Rings and Base Mold

56
Q

3 types of disposable embedding molds

A

Peel-away
Plastic Ice Trays
Paper Boats

57
Q

disposable thin plastic embedding molds, available in 3 different sizes, are simply peeled off one at a time, as soon as the wax has solidified, giving perfect even block without trimming. It may be placed directly in the chuck or block holder of the microtome.

A

Peel-Away

58
Q

such as those used in ordinary refrigerators may be recommended for busy routine laboratories. Each compartment may be utilized for embedding one tissue block, which may then be removed by bending once the wax has solidified or by smearing the inner mold with glycerin or liquid paraffin before embedding

A

Plastic Ice Trays

59
Q
  • are normally utilized for embedding celloidin blocks but are equally useful for paraffin wax blocks
  • They have the advantage of being cheap and easy to make.
  • They provide easy and accurate identification of specimen, thereby avoiding confusion and interchange of tissue blocks.
A

Paper Boats

60
Q

used to be recommended for embedding hard tissues such as bones and teeth, and for large sections of whole organs like the eye, since the delicate layers of the eyeball are difficult to keep intact when other media are used

A

Celloidin or Nitrocellulose Embedding Method

61
Q

the process by which tissues are first embedded or fully infiltrated with a supporting medium such as agar or nitrocellulose then infiltrated a second time with paraffin wax in which they are subsequently embedded (obsolete)

A

Double-Embedding

62
Q

provided superior results for light microscopic studies, particularly in hard tissues such as undecalcified bone, and for high-resolution light microscopy of tissue sections thinner than the usual 4-6 µm, such as renal biopsies and bone marrow biopsies

A

PLASTIC (RESIN) EMBEDDING

63
Q

3 types of Epoxy

A
  1. Bisphenol A (Araldite) - slow
  2. Glycerol (Epon) - low viscosity
  3. Cyclohexene dioxide (Spurr) - very low viscosity
64
Q
  • for electron microscopy
  • most widely applied
  • carcinogenic due to vinyl cyclohexane dioxide (VCD)
A

Epoxy

65
Q

were originally introduced for electron microscopy in the mid- 1950s, but have been superseded by more superior epoxides, and are now seldom used.

A

Polyester plastics

66
Q

made up of esters of acrylic or methacrylic acid, and
are used extensively for light microscopy

A

Acrylic plastics

67
Q

popular embedding medium for light microscopy because it is extremely hydrophilic, allowing many staining methods to be applied, yet tough enough when dehydrated to section well on most microtomes.

A

Polyglycol methacrylate (GMA)

68
Q
  • has found an increasing number of applications for the embedding of biological tissue for transmission electron microscopy (TEM), for the preservation and observation of fine structure not previously subjected to solvent dehydration.
  • forms only non-crosslinked straight chains on polymerization and therefore requires no hardener
A

glycol methacrylate (GMA)

69
Q

is added to the plastic as a catalyst that decomposes to form phenyl radicals acting as an active site for the polymerization of acrylics

A

Benzoyl peroxide

70
Q

widely used because of its hardness as the ideal embedding medium for undecalcified bone and is widely used for bone histomorphometry and bone marrow hematopathology.

A

methyl methacrylate (MMA)

Histopathology Laboratory (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions