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Histopath LEC > TRIMMING & MICROTOMY > Flashcards

TRIMMING & MICROTOMY Flashcards

1
Q

• Removal of excess wax using a knife or cutter after the wax block is removed from the tissue cassette or paper boat.

A

TRIMMING

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2
Q

TRIMMING

Formation of a_______(ideal shape) and exposure of the tissue surface for ease of sectioning.

A

truncated pyramid

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3
Q

Allow tissue blocks to fit into the block holder of the microtome.

A

Trimming

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4
Q

Trimming
___________
• Thicker chunk will be trimmed.
___________
• Small bits or just the edges of your tissue block will be trimmed.

A

Coarse trimming

Fine trimming

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5
Q

The process by which processed tissue, most commonly a paraffin embedded tissue, is trimmed and cut into uniformly thin slices or “sections” to facilitate studies under the microscope

A

Microtomy

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6
Q

Microtomy

The basic instrument used is a_____

A

microtome

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7
Q

capable of cutting a section at a predetermined thickness by sliding the block into a cutting tool, usually a (3), which is fixed and attached to the machine.

A

microtome

steel knife, glass or diamond blade

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8
Q

The microtome consists of three essential parts

A

Block holder

Knife carrier and knife

Pawl, Ratchet Feed Wheel and Adjustment Screws

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9
Q

Complete ribbons are picked up and transferred to a flotation bath with a (3)

A

camel hair brush
forceps
fingers

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10
Q

Incomplete sections are_____.

A

discarded

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11
Q

MICROTOME

● Principle:

A

Spring-balanced or pawl is brought into contact with, and turns the ratchet feed wheel connected to a micrometer screw, which is, in turn, rotated, moving the tissue black at a predetermined distance towards the knife for cutting sections at a uniform thickness.

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12
Q

5 types of microtome

SRRF CU

A

Sliding
Rocking
Rotary
Freezing
Cryostat
Ultrathin

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13
Q

– for cutting serial sections of large blocks of paraffin embedded tissues.

A

Rocking microtome

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14
Q
  • for cutting paraffin embedded sections.
A

Rotary microtome

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15
Q
  • for cutting celloidin embedded sections.
A

Sliding microtome

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16
Q

-for cutting unembedded frozen sections.

A

Freezing microtome

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17
Q

– for cutting frozen sections

A

Cryostat or cold microtome

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18
Q
  • for cutting sections for Electron Microscopy.
A

Ultrathin microtome

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19
Q

Rocking microtome aka

A

Cambridge microtome

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20
Q

simplest among the different types of microtomes.

A

Rocking microtome

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21
Q

Rocking microtome consists of

A

Heavy base

2 arms (lower & upper arm)

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22
Q

Rocking microtome

_______ resting on pivots and a supporting column, and attached to the micrometer screw, at the base of which is found the ratchet wheel with feed mechanism.

_______, carrying the block holder on one end by means of a screw, is connected to a lever by a piece of nylon thread.

A

lower arm

upper arm

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23
Q

Rocking microtome inventor

A

Paldwell Trefall

1881

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24
Q

Rocking microtome section thickness

A

10-12um

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25
Q

Knife of rocking microtome

A

Slightly curved plane

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26
Q

not recommended for serial sections since tissues are cut in slightly curved planes.

A

Rocking microtome

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27
Q

It is not currently favored by most laboratories because of the restrictions in size of tissue block that can be cut, and the difficulty of reorienting the block.

A

Rocking microtome

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28
Q

currently the most common type used for both routine and research laboratories, especially for sectioning paraffin-embedded tissues.

A

Rotary microtome

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29
Q

In rotary microtome

knife is fixed in a_____ position

A

horizontal

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30
Q

Rotary microtome inventor

A

Minot

1885-86

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31
Q

Rotary microtome

To cut_______ tissues

Both manual and electrically driven models are now available for cutting_____ and ______.

A

paraffin embedded

ultrathin sections and for cryostat use

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32
Q

Rotary microtome

The cutting angle (tilt) of knife is adjustable, so it can cut harder tissue.

It can cut_______-embedded sections by using a special holder to set the knife obliquely.

A

celloidin

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33
Q

Rotary microtome section thickness

A

3 and 5 µm using paraffin wax

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34
Q

It is heavier and more stable than the rocking microtome, is more complex in design and construction

A

Rotary microtome

35
Q

Rotary microtome

(A heavier knife is used, so there is_____)

Produces serial sections

A

less vibration

36
Q

more expensive

The knife is placed in a blade-up position and is therefore relatively dangerous.

A

Rotary microtome

37
Q

knife can be set obliquely for celloidin sections or straight for large refractory paraffin blocks, cutting both large and small tissues with ease;

A

Sliding microtome

38
Q

slow but very steady motion is therefore required to manipulate the instrument.

A

Sliding microtome

39
Q

It is especially recommended for cutting extremely hard and rough tissue blocks.

A

Sliding microtome

40
Q

Sliding microtome inventor

A

Adams in 1789

41
Q

most dangerous type of microtome due to the movable exposed knife.

A

Sliding microtome

42
Q

Two types of sliding microtome

A

Base-Sledge Microtome

Standard Sliding microtome

43
Q

-› electrically driven and ideal for resin-embedded decalcified bone.

A

Base-Sledge Microtome

44
Q

-> knife is moving; the most dangerous type of microtome because of the exposed, movable blade.

A

Standard Sliding Microtome

45
Q

• Both Microtome, the knife can be set obliquely for celloidin or straight large paraffin.

• Recommended for cutting “extremely” hard and rough tissue blocks.

A

Sliding microtome

46
Q

True or False

Sliding microtome

Cannot make tissue ribbons, only tissue sections.

A

True

47
Q

It was originally designed for cutting sections of very large blocks (whole brain).

A

Base sledge microtome

48
Q

Sections are cut in a perfectly flat plane, thereby making excellent serial tissue sections.

It is comparatively heavier and more stable than the ordinary sliding microtome.

The angle of the knife is adjustable

A

Base sledge microtome

49
Q

favored in laboratories where very hard tissue or large blocks are usually sectioned.

suited for sectioning specimens embedded in all forms of media, especially for cutting sections from tough tissue blocks which may offer great resistance to the knife

A

Base sledge microtome

50
Q

knife used is long (24 cm), hence it requires less honing

A

Base sledge microtome

51
Q

FREEZING MICROTOME
• Invented by:

A

Quickett (1848)

52
Q

The stage for block holder is hollow and perforated around its perimeter

A

Freezing microtome

53
Q

The microtome is firmly clamped on to the edge of the bench for use, or mounted on especially constructed shelf

A

Freezing microtome

54
Q

Freezing agent of freezing microtome

A

Freezing agent: CO2

Release into the stage & will evenly freeze block holder & tissue.

55
Q

used to cut undehydrated thin to semi-thin sections of fresh, frozen tissues, especially in instances when rapid diagnosis is required

A

Freezing microtome

56
Q

For fats & tissue
constituents that may be damaged

A

Freezing microtome

57
Q

For rapid diagnosis in the processing of neurological structures & heat sensitive tissue constituents

A

Freezing microtome

58
Q

Freezing microtome section size for neurological tissues

A

10-15 um (for neurological tissues)

59
Q

Although other microtomes can be modified for cutting frozen section, this type will give the best results and is used almost universally.

A

Freezing microtome

60
Q

the knife is moved whilst the tissue block remains static, same as sliding microtome.

A

Freezing microtome

61
Q

Cryostat aka

A

Cold microtome

62
Q

True or False

Cryostat is more common than freezing microtome.

A

True

63
Q

Used for rapid preparation of urgent tissue biopsies for intraoperative diagnosis (STAT).

A

Cryostat

64
Q

Cryostat

• Chamber:
• Average:

A

-5 to -30°C

-20 °C

65
Q

Cryostat

Thermostat:
Capable of freezing fresh tissue within…

A

2-3 minutes

66
Q

It is often housed in the frozen section room close to the operating room to allow direct consultation between surgeon and pathologist

A

Cryostat

67
Q

Sections are usually transferred directly from the microtome knife to a slide or cover glass, all of which are maintained at a low temperature

A

Cryostat

68
Q

The cryostat provides a means of preparing thin sections of fresh frozen tissues especially for _____ or _____

A

fluorescent antibody staining techniques

histochemical enzyme studies.

69
Q

Cryostat

cutting sections of…

A

4 µ

70
Q

• All the controls to the microtome are operated from the outside of the refrigerated cabinet.

A

Cryostat

71
Q

Ultrathin microtome

______(epoxy resin)

semi-thin - generally______

A

60 to 100 nm

0.5 to 1 µm

72
Q

Ultrathin microtome

used to cut very thin sections of tissue embedded in____

A

epoxy resin

73
Q

equipped with a glass or gem grade diamond knife

A

Ultrathin microtome

74
Q

Ultrathin microtome

Fixate in

A

Osmium tetroxide

75
Q

Embedding medium of ultrathin microtome

A

plastic

76
Q

Ultrathin microtome

These semi-thin sections are generally 0.5 to 1 µm thick and are mounted on a glass slide and stained to locate areas of interest under a _____prior to thin sectioning for the TEM.

Thin sectioning for the TEM is often done with a____knife

A

light microscope

gem quality diamond knife.

77
Q

Care

After sectioning, all the accumulated paraffin and small pieces of tissues must be brushed away with a ______and not allowed to stay in the microtome, since this may later interfere with the cutting of tissue blocks

A

soft brush

78
Q

-> may also be used for cleaning some parts of the microtome.

A

Xylene

79
Q

Care

After carefully drying the machine and knife holder, the parts should be wiped with______.

Prolonged and continuous application of the painted parts with____ should, however, be avoided since this reagent is capable of removing the paint.

A

xylol

xylene

80
Q

Care

Movable portions should be____ thoroughly to prevent rusting

A

oiled

81
Q

The microtome must always be_____ when not in use, to prevent accumulation of dust and other dirt which may later on interfere with the normal sectioning of tissues.

A

covered

82
Q

Have the instrument inspected at least______ by a qualified service technician.

A

once a year

83
Q

Safety

Use____ or ____ instead of fingers to pick up sections or wax fragments from blade or block face.

A

forceps or brush

84
Q

Use________ when changing blocks. The knife or blade should be removed from the microtome when the instrument is left unattended or when cleaning the instrument.

A

hand wheel lock

Histopath LEC (37 decks)

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