HCT 04 | Tissue Processing 4 (Embedding and Sectioning)

What types of microtome utilize a more concave, plane-concave knife?

(1) Base-sledge (2) Rotary (3) Rocking

Two types of sliding microtome

(1) Base-sledge type (2) Standard sliding microtome

3 different types of hones

(1) Belgium yellow (2) Arkansas stone (3) Fine carborundum

3 essential parts present in all types of microtomes

(1) Block holder (2) Knife carrier and knife (3) Pawl rachet feed wheel with adjustment screws

Other names for embedding

(1) Casting (2) Blocking

Other names for the freezing microtome

(1) Cryocut (2) Cryostat (3) Cold microtome

Two stages in sharpening the knife

(1) Honing (2) Stropping

2 types of concave knives used in a plane-concave knife

(1) Less concave (2) More concave

7 molds used for embedding

(1) Leuckhart's embedding iron (2) Compound embedding unit (3) Plastic embedding ring and base mold (4) Peel-a-way (5) Paper mold or boat (6) Plastic ice trays (7) Disposable embedding mold

Equipment that converts paraffin wax from solid to liquid state upon heating

(1) Liquid paraffin wax dispenser (2) Paraffin bath

3 types of microtome knives

(1) Plane-concave knife (2) Plane-wedge knife (3) Biconcave knife

5 types of microtome

(1) Rocking microtome (2) Rotary microtome (3) Sliding microtome (4) Freezing microtome (5) Ultrathin microtome

3 requirements to produce a good quality tissue section

(1) Skill of the microtomist (2) A sharp knife in good condition (3) Microtome in good condition

Thickness of tissue sections through xyloidin sectioning

10-15 microns

Range of the bevel angle

27-32 degrees

Average micron thickness of the tissue sections set for microtomy

5 microns (range: 4-6 microns)

Range of the clearance angle

5-10 degrees

He invented the sliding microtome and what year did he invent it in

Adams in 1789

Type of sliding microtome where the block holder is set on a heavy metal base which can be moved backward and forward under the knife during cutting

Base-sledge type microtome

Temperature to keep the tissue flotation bath in during the flattening of the tissue sections

Between 45-50 degrees Celsius or 6-10 degrees Celsius below the melting point of the wax

It is the angle formed between the cutting edges of the knife

Bevel angle

Most rarely used microtome knife

Biconcave knife

Type of microtome knife whose 2 sides are both concave

Biconcave knife

Part of the microtome where the tissue is held in position

Block holder

It is the angle formed between the tissue block and the cutting edge of the knife between two smooth plane surfaces

Clearance angle

Other name for honing

Coarse sharpening

When is a plane-wedged knife used for?

Cutting frozen sections or hard and difficult specimens embedded in paraffin blocks

When is a biconcave knife utilized

Cutting paraffin sections on a rotary microtome

A process whereby the impregnated tissue is placed into a precisely arranged position in a mold containing melted paraffin which is then allowed to solidify

Embedding

Designates all materials used to infiltrate, support, and enclose specimens which would be subsequently cut into thin sections

Embedding medium

The rotation of the handwheel should be done in a rapid, counter-clockwise, and even rotation to produce a tissue ribbon (t/f)

False; clockwise

The pawl rachet feed wheel with adjustment screws is located on the right side of the microtome when facing the machine (t/f)

False; on the left side

The medium used for embedding is the different from the medium used for infiltration (t/f)

False; they're the same

Other name for stropping

Fine sharpening

When is a less concave, plane-concave knife used?

For cutting celloidin embedded tissue

When is more concave, plane-concave knife used?

For cutting paraffin section

Equipment used to pick up the tissue from the paraffin bath to the mold

Forceps

Direction of how a knife is honed

Heel (handle end) to the toe (head portion)

It is the removal of gross nicks and irregularities on the knife edge

Honing

Used to hasten solidification and prevent crystallization of the paraffin block during embedding

Ice bath or cold water

Part of the microtome used for actual cutting of tissue sections

Knife carrier and knife

Commonly used adhesive which lets the tissue sections adhere or stick to the glass slides

Meyer's egg albumin

Machine used for cutting

Microtome

The process whereby the paraffin embedded tissue is trimmed and cut into uniformly thin sections to facilitate studies under the microscope

Microtomy

He invented the rotary microtome and what year did he invent it in

Minot in 1885-85

Where to hold the glass slides

On the sides/edges

He invented the rocking microtome and what year he invented it in

Paldwell Trefall in 1881

Part of the microtome used to line up the tissue block in proper position with the knife

Pawl rachet feed wheel with adjustment screws

Microtome knives where one side is flat and the other is concave

Plane-concave knife

Type of microtome knife whose sides are both straight

Plane-wedge knife

He invented the freezing microtome and what year did he invent it in

Queckett in 1848

Microtome used for cutting serial sections of large blocks of paraffin-embedded tissue

Rocking microtome

Microtome used for cutting paraffin embedded sections (most common used)

Rotary microtome

Microtome used for cutting celloidin sections

Sliding microtome

What types of microtome utilize a less concave, plane-concave knife?

Sliding microtome

The most dangerous type of microtome

Standard sliding microtome

Type of sliding microtome wherein the block remains stationary while the knife is sliding backward and forward during sectioning

Standard sliding microtome

It removes the "burr" that forms when honing and polishes and sharpens the cutting edge of the knife

Stropping

First equipment used to remove the wrinkles and folds on the tissue sections

Teasing needle

This functions to flatten or spread the tissue sections

Tissue flotation bath

Purpose of placing the trimmed tissue blocks in ice prior to cutting

To harden the paraffin block since it becomes soft in room temp.

Reason for holding the glass slide on its sides/edges

To keep it clean and free from dust, oily substances, and fingerprints

Reason for keeping the tissue flotation bath at a lower temperature for flattening the tissue sections compared to infiltration

To prevent overheating which causes artefactual separation of the tissue sections

Direction of how a knife is stropped

Toe (head portion) to the heel (handle end)

Process of removing excess wax from the paraffin block before sectioning

Trimming

Xyloidin sectioning makes it impossible to produce ribbons (t/f)

True

Microtome used for cutting ultrathin sections for electron microscopy

Ultrathin microtome

Preferred method for xyloidin sectioning to avoid dehydration and shrinkage

Wet method

Sectioning that does not require chilling before cutting

Xyloidin sectioning