PARTS OF THE MICROTOME- LABORATORY

Blocking

is a step done hand in hand with Embedding

individual mold

is used because blocks are produced after solidification

big mold tray

is used, use a sharp knife to separate one tissue from another

Trimming

is merely removing the excess wax

2mm

Trimming- At least _____ of wax should surround the tissue block.

Trimmed tissue

block allows easy sectioning.

Sectioning/ Microtomy

blocks are cut into uniformly thin slices or “sections”

BLOCK HOLDER

tissue is held in a position

KNIFE CARRIER AND KNIFE

cutting of tissue sections

PAWL, RACHET FEED WHEEL AND ADJUSTMENT SCREWS

lines the block in proper position with the knife, adjusting the proper thickness

ROCKING

cutting serial sections of large blocks of paraffin embedded tissues

ROTARY

Paraffin embedded tissues

SLIDING

Celloidin embedded tissues

FREEZING

unembedded frozen sections

ULTRATHIN

sections for Electron Microscopy

ROCKING MICROTOME

The simplest microtome

ROCKING MICROTOME

The block makes contact with the knife

Paldwell Trefall

ROCKING MICROTOME- Invented by

1881

ROCKING MICROTOME- Invented in

Cambridge Microtome

ROCKING MICROTOME- Also called as the

10-12 um

ROCKING MICROTOME- Can cut ________ of sections

ROTARY MICROTOME

Most common type for both routine and research laboratories

ROTARY MICROTOME

Allows excellent serial sectioning; Heavier and more stable than the Rocking Microtome

ROTARY MICROTOME

More expensive

ROTARY MICROTOME

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

Minot

ROTARY MICROTOME- Invented by

1885-1886

ROTARY MICROTOME- Invented in

SLIDING MICROTOME

Recommended for extremely hard and tough tissues

SLIDING MICROTOME

Most Dangerous type of microtome because of the movable exposed knife.

Adams

SLIDING MICROTOME- Developed by

1789

SLIDING MICROTOME- Developed in

Base Sledge Microtome

Ideal for Resin-embedded Decalcified Bone

Standard Sliding Microtome

The block remains stationary and the knife is moved backward and forward

FREEZING MICROTOME

To cut undehydrated tissues in a frozen state, especially for rapid diagnosis.

FREEZING MICROTOME

Histological demonstration of fat is needed. Certain neurological structures are to be studied

Queckett

FREEZING MICROTOME- Invented by

1848

FREEZING MICROTOME- Invented in

Carbon Dioxide

Use of ____________ as the freezing agent.

CRYOSTAT

Refrigerated apparatus used in fresh tissue microtomy

-5 to -30 Celsius

CRYOSTAT- Usually a Rotary Microtome, kept inside a cold chamber between

2-3 minutes

CRYOSTAT- Tissues can be frozen within

4 u

CRYOSTAT- Cutting of tissues sections of

CRYOSTAT

For fluorescent Antibody staining techniques, histochemical enzyme studies

CRYOSTAT

Intraoperative diagnosis

ULTRATHIN MICROTOME

Knife used is usually selected fragments of broken plate glass- Diamond Knife

0.5 micra

ULTRATHIN MICROTOME- Cutting tissues at

ULTRATHIN MICROTOME

for Electron Microscopy

Small tissues

ULTRATHIN MICROTOME- fixed in Osmium Tetroxide, Embedded in Plastic

GLASS/ DIAMOND KNIVES

for Ultrathin Microtomy

DISPOSABLE KNIVES

more commonly used; coated with polytetrafluoroethylene for easy ribboning

PLANE CONCAVE KNIFE

Usually 25mm in length

PLANE CONCAVE KNIFE

one side is flat, other is concave

BICONCAVE KNIFE

Usually 120mm in length

BICONCAVE KNIFE

cutting paraffin blocks in Rotary Microtomes

PLANE WEDGE KNIFE

Usually 100mm in length

PLANE WEDGE KNIFE

both sides are straight

PLANE WEDGE KNIFE

For Frozen sections, hard and tough tissues in paraffin block

PLANE WEDGE KNIFE

Used in Base-Sledge type or Sliding Microtome

More concave sides

are for paraffin sections, base-sledge, rotary or rocking microtome

Less concave sides

are recommended for Celloidin blocks