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Histopath LEC > TRIMMING & MICROTOMY > Flashcards

TRIMMING & MICROTOMY Flashcards

(84 cards)

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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
Knife of rocking microtome
Slightly curved plane
26
not recommended for serial sections since tissues are cut in slightly curved planes.
Rocking microtome
27
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.***
Rocking microtome
28
currently the most common type used for both routine and research laboratories, especially for sectioning paraffin-embedded tissues.
Rotary microtome
29
In rotary microtome knife is fixed in a_____ position
horizontal
30
Rotary microtome inventor
Minot 1885-86
31
Rotary microtome To cut_______ tissues Both manual and electrically driven models are now available for cutting_____ and ______.
paraffin embedded ultrathin sections and for cryostat use
32
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.
celloidin
33
Rotary microtome section thickness
3 and 5 µm using paraffin wax
34
It is heavier and more stable than the rocking microtome, is more complex in design and construction
Rotary microtome
35
Rotary microtome (A heavier knife is used, so there is_____) Produces serial sections
less vibration
36
more expensive The knife is placed in a blade-up position and is therefore relatively dangerous.
Rotary microtome
37
knife can be set obliquely for celloidin sections or straight for large refractory paraffin blocks, cutting both large and small tissues with ease;
Sliding microtome
38
slow but very steady motion is therefore required to manipulate the instrument.
Sliding microtome
39
It is especially recommended for cutting extremely hard and rough tissue blocks.
Sliding microtome
40
Sliding microtome inventor
Adams in 1789
41
most dangerous type of microtome due to the movable exposed knife.
Sliding microtome
42
Two types of sliding microtome
Base-Sledge Microtome Standard Sliding microtome
43
-› electrically driven and ideal for resin-embedded decalcified bone.
Base-Sledge Microtome
44
-> knife is moving; the most dangerous type of microtome because of the exposed, movable blade.
Standard Sliding Microtome
45
• Both Microtome, the knife can be set obliquely for celloidin or straight large paraffin. • Recommended for cutting "extremely" hard and rough tissue blocks.
Sliding microtome
46
True or False Sliding microtome Cannot make tissue ribbons, only tissue sections.
True
47
It was originally designed for cutting sections of very large blocks (whole brain).
Base sledge microtome
48
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
Base sledge microtome
49
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
Base sledge microtome
50
knife used is long (24 cm), hence it requires less honing
Base sledge microtome
51
FREEZING MICROTOME • Invented by:
Quickett (1848)
52
The stage for block holder is hollow and perforated around its perimeter
Freezing microtome
53
The microtome is firmly clamped on to the edge of the bench for use, or mounted on especially constructed shelf
Freezing microtome
54
Freezing agent of freezing microtome
Freezing agent: CO2 Release into the stage & will evenly freeze block holder & tissue.
55
used to cut ***undehydrated thin to semi-thin sections of fresh, frozen tissues,*** especially in instances when rapid diagnosis is required
Freezing microtome
56
For fats & tissue constituents that may be damaged
Freezing microtome
57
For rapid diagnosis in the processing of neurological structures & heat sensitive tissue constituents
Freezing microtome
58
Freezing microtome section size for neurological tissues
10-15 um (for neurological tissues)
59
Although other microtomes can be modified for cutting frozen section, this type will give the best results and is used almost universally.
Freezing microtome
60
the knife is moved whilst the tissue block remains static, same as sliding microtome.
Freezing microtome
61
Cryostat aka
Cold microtome
62
True or False Cryostat is more common than freezing microtome.
True
63
Used for rapid preparation of urgent tissue biopsies for intraoperative diagnosis (STAT).
Cryostat
64
Cryostat • Chamber: • Average:
-5 to -30°C -20 °C
65
Cryostat Thermostat: Capable of freezing fresh tissue within…
2-3 minutes
66
It is often housed in the frozen section room close to the operating room to allow direct consultation between surgeon and pathologist
Cryostat
67
Sections are usually transferred directly from the microtome knife to a slide or cover glass, all of which are maintained at a low temperature
Cryostat
68
The cryostat provides a means of preparing thin sections of fresh frozen tissues especially for _____ or _____
fluorescent antibody staining techniques histochemical enzyme studies.
69
Cryostat cutting sections of…
4 µ
70
• All the controls to the microtome are operated from the outside of the refrigerated cabinet.
Cryostat
71
Ultrathin microtome ______(epoxy resin) semi-thin - generally______
60 to 100 nm 0.5 to 1 µm
72
Ultrathin microtome used to cut very thin sections of tissue embedded in____
epoxy resin
73
equipped with a glass or gem grade diamond knife
Ultrathin microtome
74
Ultrathin microtome Fixate in
Osmium tetroxide
75
Embedding medium of ultrathin microtome
plastic
76
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
light microscope gem quality diamond knife.
77
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
soft brush
78
-> may also be used for cleaning some parts of the microtome.
Xylene
79
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.
xylol xylene
80
Care Movable portions should be____ thoroughly to prevent rusting
oiled
81
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.
covered
82
Have the instrument inspected at least______ by a qualified service technician.
once a year
83
Safety Use____ or ____ instead of fingers to pick up sections or wax fragments from blade or block face.
forceps or brush
84
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.
hand wheel lock

Histopath LEC (37 decks)

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