SAS 5: Infiltration, Embedding, and Microtomy (Part II) Flashcards
This is after impregnating the tissue where it is placed into a mold containing the embedding medium and allowed to solidify.
Embedding
Ideally, the embedding medium should match the tissue type in ____ and ____
strength and hardness
Types of Blocking-Out Methods
- Leuckhart’s Embedding Mold
- Compound Embedding Ring and Base Mold
- Disposable Embedding Molds
It 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
Leuckhart’s Embedding Mold
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
Leuckhart’s Embedding Mold
Consists of a special stainless steel base mold fitted with a plastic embedding ring, which latter serves as the block holder during cutting
Plastic Embedding Ring and Base Mold
Equipped with a warm plate to manage the impregnated specimen, and a cold plat at -5C for rapid solidification of the block.
Tissue Tek
Disposable embedding molds:
- Peel-Away
- Plastic Ice Tray
- Paper Boat
It is a 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 places directly in the chuck or block holder of the microtome,
Peel-Away
It may be recommended for busy routine laboratories. Each compartment of this may be utilized for embedding one tissue bloc, which may then be removed by bending the plastic tray once the wax has solidified or by smearing the inner mole with glycerin or liquid paraffin before embedding.
Plastic Ice Tray
Normally utilized for embedding celloidin blocks but are really equally useful for paraffin wax blocks. They have the advantage of being cheap and easy to make. They provide accurate identification of specimens, thereby avoiding confusion and interchange of tissue blocks
Paper boat
Process by which the processed tissue is trimmed and cut unto uniformly thin slices or “sections” to facilitate studies under the microscope
Microtomy
Capable of cutting a section at a predetermined thickness by sliding the block into a cutting tool, usually a steel knife, glass and diamond blade, which is attached to the machine
Microtome
Blades that are used in Microtome
Glass and diamond blade
3 Essential Parts of Microtome
- Block Holder
- Knife Carrier and Knife
- Pawl, Ratchet Feed Wheel and Adjustment screws
Parts of microtome where the tissue is held in position
Block holder
Parts of microtome for actual cutting of tissue sections
Knife Carrier and Knife
Parts of microtome used to line up the tissue block in proper position with the knife, adjusting the proper thickness of the tissue for successive sections
Pawl, Ratchet Feed Wheel and Adjustment Screws
5 kinds of Microtomes:
- Rocking Microtome - Paldwell Trefall
- Rotary Microtome - Minot
- Sliding Microtome - Adams
- Freezing Microtome - Queckett
- Ultrathin Microtome
- Cryostat or cold microtome
A microtome used for cutting serial sections of large blocks of paraffin embedded tissues
Rocking Microtome
Used for cutting paraffin embedded sections
Rotary Microtome
Used or cutting celloidin embedded sections
Sliding Microtome
Used for cutting unembedded frozen sections
Frozen Microtome
Used for cutting sections for electron microscopy
Ultrathin Microtome
Used for cutting sections for Electron Microscope
Cryostat or cold microtome
It is the simplest microtome
Rocking (Cambridge Microtome)
Most common type used for both routine and research laboratories
Rotary Microtome
In rotary microtome, the thickness of section is regulated by
ratchet feed wheel
used to come in contact with the ratchet wheel w/c in turn rotates the micrometer screw
Pawl
make the block parallel to the microtome knife at all planes
Adjustment screw
2 types of sliding microtome
- Base-Sledge Microtome
- Standard Sliding Microtome
Mainly developed for cutting celloidin embedded tissue blocks
Standard Sliding Microtome
More dangerous because of the movable knife
Standard Sliding Microtome
It is the most dangerous type of microtome due to the movable exposed knife
Sliding Microtome
It is used to cut undehydrated thin to semi-sections of fresh, frozen tissues, especially in instances when rapid diagnosis is required
Freezing Microtome
Although other microtomes can be modified for cutting frozen section, this type will give the best results and is almost used universally
Freezing microtome
A refrigerated apparatus used when for fresh tissue microtomy
Cryostat or Cold Microtome
Cutting sections or sizes of cryostat
4 Micra
Provides sections for fresh tissue examination esp. Fluorescent Antibody Staining techniques of Histochemical
Cryostat or Cold Microtome
Capable of freezing fresh tissues within 2-3 minutes
Thermostat
Used for urgent biopsies for intraoperative diagnosis
Cryostat or Cold Microtome
Primarily used for cutting sections at 0.5 micra for electron microscopy
Ultrathin Microtome
The specimen used in ultrathin microtome is small and fixed with ______ and embedded in plastic
osmium tetroxide
