Lec 4: Sectioning & Embedding Flashcards

1
Q

Placing the tissue in the paraffin wax in a precisely arranged position

A

Embedding

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2
Q

Refers to the material used to infiltrate, support, and enclose specimens that will cut into thin sections.

A

Embedding media

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3
Q

Purpose of ice

A
  • prevent paraffin crystal formation
  • accelerate hardening
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4
Q

Types of Embedding Molds

A
  • Pop-out hinge embedding mold
  • Leuckhart’s embedding mold
  • Compound embedding unit
  • Plastic embedding rings & base mold
  • Disposable embedding mold
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5
Q

The type of embedding mold we use in the laboratory.

A

Pop-out hinge embedding mold

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6
Q
  • consists of two L-shaped strips of heavy brass/metal arranged on a flat metal plate
A

Leuckhart’s embedding mold

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7
Q

Advantages of Leuckhart’s Embedding Mold

A
  • can adjust its size to the size of the specimen
  • produces even blocks with parallel sides
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8
Q

Advantages of Leuckhart’s Embedding Mold

A
  • can adjust its size to the size of the specimen
  • produces even blocks with parallel sides
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9
Q
  • made up of series of interlocking plates resting on a flat metal base, forming several compartments
A

Compound Embedding Unit

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10
Q

Compound Embedding Unit
1. Advantage
2. Disadvantage

A
  1. Embedding more specimens at a time
  2. Labels can be removed
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11
Q
  • an automated embedding unit
  • consists of a special stainless steel base mold fitted with a plastic embedding ring
A

Plastic embedding ring and base mold

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12
Q

Advantage of Plastic embedding ring and Base mold

A

The plastic embedding ring serves as a block holder during cutting

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13
Q
  • peel away
  • paper boat
  • plastic ice trays
A

Disposable Embedding Mold

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14
Q

Temperature of Calibration for the Electric Paraffin Wax Dispenser

A
  • 58 to 60°C

OR

  • 2 to 5°C above the melting point of paraffin
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15
Q

Purpose of Paraffin Bath

A

To place the impregnated tissues before embedding

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16
Q
  • removing excess wax at the sides, top, and bottom of the block
  • exposes tissue surface
A

Trimming

17
Q

TRIMMING
1. All sides are ___ to form a ____ prism or ____.
2. Thickness of sections.
3. A series of tissue sections.

A
  1. All sides are parallel to form a four-sided prism or truncated pyramid.
  2. 4 to 6 microns
  3. Ribbon
18
Q

What are the requirements for a successful sectioning of paraffin blocks? (3)

A
  • Microtome
  • Sharp (disposable) knife
  • Microtomist’s / Technologist’s skills
19
Q
  • by Paldwell Trefall (1881)
  • for cutting serial sections of large blocks
  • phased out
A

Rocking Microtome

20
Q
  • by Minot (1885-1886)
  • for paraffin-embedded sections
A

Rotary Microtome

21
Q
  • by Adams (1789)
  • for celloidin-embedded sections
A

Sliding Microtome

22
Q

2 types of Sliding Microtome

A
  1. Base Sledge Microtome
    • block holder moves under the knife
  2. Standard sliding Microtome
    • block is stationary, while knife moves
23
Q
  • by Queckett (1848)
  • a Rotary Microtome inside a refrigerated chamber
A

Freezing Microtome

24
Q
  • for STAT diagnosis
  • for cutting unembedded frozen sections
A

Freezing Microtome

25
Q
  • latest freezing Microtome
  • for cutting frozen samples
A

Cryostat Microtome

26
Q
  • for cutting sections for Electron Microscopy
  • 0.5 to 1 micro thickness
A

Ultrathin Microtome

27
Q
  • automated
  • vibrates
A

Vibratome

28
Q

MICROTOME PARTS
1. For cutting of tissue section
2. Found on the right side of Microtome, and operates in a clockwise rotation
3. Found on the left side of Microtome, and adjusts the block holder forward/backward from the knife.
4. Holds the block tightly during cutting

A
  1. Knife holder & knife
  2. Flywheel or Handwheel
  3. Pawl Ratchet Feed Wheel
  4. Block Holder
29
Q

The angle formed between the cutting edge of the knife
- held constant
- a.k.a. Facet

A

Bevel Angle

30
Q

The angle between the tissue block and the cutting edge of knife

A

Clearance Angle

31
Q
  1. What is the Clearance Angle?
  2. Give the Bevel Angle.
A
  1. 0 to 15°
  2. Usually 27 to 32°
32
Q
  • one side of the knife is flat while the other is concave
A

Plane-Concave knife

33
Q
  1. The less concave knife is used for cutting ___ embedded tissue sections.
  2. The more concave knife is used to cut ___ embedded tissue sections.
A
  1. Celloidin
  2. Paraffin
34
Q

Used for cutting paraffin sections but a rarely used

A

Biconcave knife

35
Q
  • Most commonly used
  • disposable
  • both sides are straight
A

Plane wedge knife

36
Q

Type of knife used for frozen sections or extremely hard specimen blocks.

A

Plane wedge knife

37
Q

Used for trimming and semi thin sectioning of tissue blocks for electron microscopy

A

Glass knife

38
Q
  • Used to cut any type of resin block for electron microscopy
  • brittle and expensive but very durable
A

Diamond knife / Broken Plate Glass